Ep 169 Pregnancy: Act 2

Episode Transcript
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Speaker 1 (00:00):
We want to start with a disclaimer that throughout this
series we feature explanations and stories that include some heavy material,
including early pregnancy, loss, stillbirth, and other traumatic experiences of pregnancy, childbirth,
and the postpartum period.

Speaker 2 (00:17):
I'm Siena. I'm twenty eight years old and twenty eight
weeks pregnant with my first child. It seems like a cliche,
but my most daunting pregnancy symptom has been mourning sickness.
I was aware that it was a misnomer and that
it would not be restricted to the morning, but my
biggest surprise was how frequent, long, and intense morning sickness is.

(00:37):
I didn't expect to lose weight during the first time
master or be woken up at one am because of
the sudden urge to vomit. I'm not a stranger to vomiting.
I've thrown up before with the flu, food poisoning, intense migraines,
anxiety episodes, and of course after a night of having
a little bit too much fun, as they say, But

(00:57):
morning sickness is different. It feels similar to motion sickness,
like you're on a boat all the time when there's
nothing in your stomach. The urge to throw up is
so intense, and you end up throwing up this thick,
bright yellow fluid that looks like, honestly like lemon gatorade.

(01:18):
I had my eyewatch give me sound warnings from my
own vomiting, saying just ten minutes at this level can
cause temporary hearing loss, and in my experience, the heaving
has been so intense that even if I just went
to the bathroom, I still end up peeing myself. It's
just so aggressive. I actually have to wear diapers now

(01:39):
just in the off chance that I happen to throw up,
and that's just something I've accepted as part of my
life now. With my pregnancy journey, it has been a challenge,
especially with working full time and having to commute two
and a half hours every day. You never know when
morning sickness is going to strike, so I even have
little bags in my car. My morning sickness started at

(02:02):
week five and was pretty much all day every day
until week twenty two. I got a little bit of
a break, and then it started up again around week
twenty six.

Speaker 1 (02:15):
Although it's no longer all day.

Speaker 2 (02:17):
It is truly just in the morning usually, and I've
tried all the remedies that they tell you, ginger B six,
unise pressure point bands, the list goes on. Zil friend
has worked the best for me, but it's still very
hit or miss on whether or will work on any
given day.

Speaker 3 (02:38):
When I went in from my first ultrasound at seven weeks,
the doctor was able to see a gestational sack and
a yolk sack, but no fetal pull. My doctor tried
to assure me that it was possible I wasn't as
far along as I'd thought, but I had been tracking
my ovulation and I knew this wasn't a good sign,
since this was a deeply wanted pregnancy. My doctor suggested

(02:59):
we win week and do another ultrasound at eight weeks.
The ultrasound showed some growth, a fetal pull, and a heartbeat.
At first, I felt so relieved, certain that progress from
the week before meant that maybe things would actually be okay.
But then my doctor explained that the embryo was measuring
less than six weeks and the heartbeat was only eighty four.

(03:22):
When I got home, I turned to Google and found
a study that said first trimester heart rates under ninety
had a quote dismal prognosis The following week, when I
was nine weeks into my pregnancy, I went in for
my final ultrasound, which showed an embryo measuring only six
weeks one day and no heart beat. My doctor was
able to schedule me for a DNC the next day.

(03:45):
My whole pregnancy, I had no indication that anything was wrong.
I had strong dark lines on my home pregnancy test,
and early blood tests showed my hCG doubling at an
appropriate rate. I felt lucky that I was experiencing only
mild nausea, but I did have all the usual pregnancy symptoms,
and I had no bleeding or spotting at all, no cramping,

(04:08):
absolutely nothing that led me to think my pregnancy wasn't
progressing exactly as it should. I knew miscarriage was common,
especially for women in their late thirties like me, but
I always assumed that there would be some kind of
outward sign. Going through a missed miscarriage led to feelings
of profound betrayal. My pregnancy wasn't viable and my body

(04:29):
had no idea. I feel as though I am no
longer able to trust the signals that my body is sending.

Speaker 1 (05:00):
New Thank you all so much for sharing your story

(05:24):
with us, and really a huge thank you to everyone
who has written in with their experiences. We read each
and every single one of the hundreds of first hand
accounts that people submitted, and we're so grateful and truly
honored that you felt like you could share those with us,
and we tried to include as many of your stories
as possible and you'll hear more first hand accounts throughout

(05:47):
the rest of this episode and the other episodes in
this series.

Speaker 4 (05:50):
Yeah, thank you again. It really was a huge privilege
to be able to read all of your stories listen
to all of the stories that you guys sent in.
I genuinely like cried through, oh my most of whether
it was happy or sad tears. So really, thank you
again so much from the bottom of our hearts for
sharing all of your stories with.

Speaker 1 (06:07):
Us, truly.

Speaker 5 (06:08):
Yeah. Hi, I'm erin Welsh and I'm erin Allman Updy.

Speaker 1 (06:12):
And this is this podcast will kill You.

Speaker 4 (06:14):
Today is episode two of our four part series, four
parts on pregnancy. Yep, yeah, yet again coming to you
from the exactly right studios.

Speaker 1 (06:24):
I know, I feel like I'm getting more used to
it now.

Speaker 5 (06:27):
Yeah, it's good. It's going to be like this is
this is the new normal.

Speaker 1 (06:29):
This is the new normal. But before we get into
this episode, we want to share a few words about
what these four episodes will cover. And if you listen
to our first episode, this will sound familiar to you,
but in case this is your first time tuning in,
welco just want to go everything over again. Yes, welcome,
but we also want to get into the language that

(06:51):
we'll be using and our goals with creating this series.
So we decided early on to dedicate four episodes to
cover pregnancy, one for E to trimester.

Speaker 5 (07:00):
Not enough, we realized early on, but alas.

Speaker 1 (07:03):
Very very much not enough. And yeah, and so we
we did realize this, and you know, we're not going
to be able to cover everything, and throughout the series
we started to jot down like different ideas for future episodes,
and so do keep in mind that, you know, if
you're listening in and you're like, oh, I want to
know more about that, Hey, send us your idea. Yeah,
you know, maybe we will cover it in the future episod'

(07:23):
sure we will, I'm sure that we will.

Speaker 4 (07:25):
So knowing that this entire series will likely not answer
all of your questions about pregnancy or cover every experience
that a person can have during pregnancy. Pregnancy is an
incredibly individual experience, as highlighted by all of our first
hand accounts.

Speaker 5 (07:40):
But what we aim to.

Speaker 4 (07:41):
Do with this whole series is take you through the
broad changes that we see in the human body and
that you might experience during pregnancy, childbirth, and the postpartum period,
and then also explore the historical and today especially the
evolutionary aspects of pregnancy and childbirth. So each episode very
roughly corresponds to each trimester. So last week we covered

(08:04):
the first trimester, how you even know whether or not
you're pregnant, and what was happening in very early development yep.

Speaker 1 (08:12):
Then today and our second episode, we're going to talk
about the amazing organ that is the placenta and some
of the physiological changes which are really I'm so excited
to learn more about what is happening. Okay, I can't
tell you how I have two more episodes to like
briefly go through, but we're gonna talk today about the

(08:33):
placenta and these physiological changes that someone will experience as
they go through pregnancy, including some of the complications that
might arise.

Speaker 4 (08:40):
And then next week in our third episode, we'll talk
about childbirth itself, will cover labor, all of the different
modes of delivery, and then the history of cesarean sections Yep,
it's gonna be good.

Speaker 1 (08:51):
It's gonna be good. And then finally, our fourth episode,
which happens to be our season finale, will be about
this concept of the fourth trimester, exploring the changes that
happen after pregnancy, and we're also going to be talking
big picture history about overall medicalization of pregnancy and childbirth
and how the transition from home to hospital happened and

(09:13):
some of the consequences of that.

Speaker 4 (09:16):
We intend for all of these episodes to be inclusive
of all families, and we recognize that not everyone who
experiences pregnancy identifies as a woman, so we try wherever
we can to use general neutral language such as pregnant person,
while at the same time, we recognize that a lot
of what we're going to discuss when it comes to
medical bias during pregnancy and childbirth, both historically and today,

(09:39):
really is the result of gender discrimination as well as racism,
and so in those contexts we will also be using
the term women and women, and throughout these episodes will
be using terms like mother or maternal and paternal as
these are terms that are very often used in the
scientific and medical literature.

Speaker 1 (09:56):
And we also want to acknowledge that there is no
such thing as a normal pregnancy. Yeah right, there is
no textbook pregnancy. There's plenty of textbooks about pregnancy, yes,
but when it comes to pregnancy, there's no textbook example. Yeah,
but we do want to also provide a baseline of
the expected physiologic and anatomic changes that occurred during pregnancy,

(10:17):
because that can help us to understand where these complications
are coming from and what we actually mean by complication exactly.

Speaker 5 (10:24):
Yeah.

Speaker 4 (10:25):
And so now today we enter the second trimester. We
shall but first first quarantine any time.

Speaker 1 (10:34):
And we are drinking again.

Speaker 4 (10:36):
Great expectations, great expectations. Yeah, I do have great expectations
for this episode. I have great expectations for this whole
series too. Yeah, remind us, Aaron, what is in great expectations?

Speaker 1 (10:48):
Of course, it is blackberries and muddled with mint, some
ginger ale and lemon. It's a plus.

Speaker 4 (10:56):
Plusy Berita for a pregnancy series for obvious reasons. It's
great And if you haven't already, please do check out
YouTube where you can find the exactly right network channel
that now includes our content, including a very special quarantine
recipe by Georgia Hartstark made just for this series.

Speaker 1 (11:16):
We're thrilled and we'll also be posting the recipes for
this quarantining plus suber rita set on our social media
and as well as our website. This podcast will kill
you dot com?

Speaker 5 (11:27):
Have you been there yet?

Speaker 1 (11:28):
I get to shut it again to you?

Speaker 4 (11:31):
On our website, This podcast will kill you dot Com,
you can find so many incredible things. For example, you
can find transcripts from each and every one of our episodes.
You can find a good Reads list from uh where
Aaron Welsh like story books mostly.

Speaker 1 (11:44):
There's also a bookshop dot org affiliate.

Speaker 4 (11:45):
Again, I was going to say that this time, I
forgot it last time. We've also got merch, some pretty
incredible merch that we're wrapping today. If you're seeing this
on video. What else do we have? We have sources
from every single one of our episodes. We have links
to Bloodmobile who provide it's the music for all of
our episodes. We've got a contact us form, a first
hand account form. Have you been to our website yet?

Speaker 1 (12:08):
No one is gonna want to go. They're like, I've
seen it all. I've heard you talk about it all.

Speaker 5 (12:12):
What else?

Speaker 1 (12:12):
What else do I need?

Speaker 5 (12:13):
Nothing new?

Speaker 1 (12:14):
Nothing new?

Speaker 5 (12:15):
Okay, shall we think? We shall?

Speaker 4 (12:18):
I don't have any other business for today. Same so
me Aaron all about the placenta.

Speaker 1 (12:25):
I really can't wait. Good, Let's take a break out
and then and then I'll get started.

Speaker 6 (12:29):
Okay.

Speaker 3 (12:46):
Hi.

Speaker 7 (12:47):
My name is Tracy and I was thirty years old
and went off the birth control pill. I had been
on it since I was sixteen. Hoping for the best,
my husband and I went for it. Three months into
being off the pill, I was late having my period.
It was a Friday night and I would normally be
having a nice gen and tonic to greet the weekend,
so I went to the store and bought a pregnancy

(13:08):
test and immediately took it. It was negative. Okay, I
guess I will be having a J ANDT and went
into the kitchen to mix up my favorite cocktail. Five
days later, on April first, I had a regular checkup
at my o BA. She and I talked about what
my plan was and that I was officially off the pill.
I did the normal things at the appointment, you're in sample, etc.

(13:30):
She was gone for a bit and when she came
back into the room, she said, well, this is no
April Fool's joke, but you're pregnant. WHOA Okay. I went
home to tell my husband and thought I'd have a
little fun with the fact that it was April Fool's Day. So,
aside from being totally shocked, we were excited and a
bit terrified. The next week, I went into the doctor's
office to have my hCG levels measured. My doctor said

(13:53):
they weren't great, but perhaps that is why I got
a negative reading when I had taken the test. I
would need to come back into the office a few
days later to see if they had increased. But they
had not increased. They should be doubling. At this point
I figured this pregnancy might not make it. But the
good news was as I had become pregnant and I
could try again. A few days later, I went back in. Nope,

(14:16):
not have any luck with the numbers. I went back
several times over a couple of weeks, and it just
didn't seem like this is going to happen. Then a
couple of weeks into the process, I went in for
yet another test, and my doctor came into the exam
room and said, your numbers are all great. Everything had
rebounded and I was exactly where I should be, So

(14:37):
I thought I could get a little excited now from
then on out, Aside from feeling very dizzy and sick
for four months, she came bounding out a week early,
a healthy baby girl, and now she is about to
start her third year of medical school. You never really
know how things are going to play out. And yes,
she is the one who got me hooked on tp WK.

Speaker 8 (15:00):
Why Hi. My name is Sarah and I live in Oxydghire, England,
with my husband Mike and our younger son Ethan. Like
many people, I didn't actually know my blood group until
I became pregnant. Thankfully, being Reese's negative made very little
difference to either of my first two pregnancies. I had
the routine anti D injections and both boys were born

(15:21):
full term and healthy. Sadly, my third pregnancy ended in
early miscarriage. No reason was found and I was reassured
that it wasn't connected to Reese's disease. However, when I
became pregnant with Ethan the following year, signs of a
Reese's reaction appeared very early. A blood test showed the
presence of antibodies that were found to be resistant to
anti D. Thankfully, the antibody levels remained low and regular

(15:44):
skins reassured us that he was growing as expected. Each
week that passed felt like a victory. Unfortunately, at about
five months, the antibody levels rose sharply. Regular checkups continued
as we monitored him for any sign of distress. The
plan was supposedpone any intervention for as long as we could.
We made it to seven months before the scans showed
that he was developing fetal anemia. He needed a blood

(16:07):
transfusion to limit the effects of the anemia and to
give him more time before delivery became necessary. Despite signing
all of the waivers who really weren't prepared for the
transfusion to fail and for an emergency CEA section to
be performed to save his life. I vividly remember the
shock of seeing him for the first time, so small
in his incubator, covered in wires, with a machine breathing

(16:29):
for him. It just didn't feel real. I was dischonged
a few days after Ethan was born, and going home
without him was one of the hardest moments in my life.
My husband's paternity leave was soon over, and I then
faced continuing to recover from surgery while caring for our
older boys and trying to visit the hospital as often
as possible. Slowly, Ethan became stronger and he worked his

(16:50):
way through the nurseries in a nicu and scaboo. Finally,
after eight long weeks, we got to bring him home
just a few days before his due date and without
the need for any additional oxygen support. Our four pound
Premium is now a happy, very tall, thirteen year old
with a brilliant sense of humor. His difficult start in
life has had no effect on his health, and most

(17:10):
people can't believe that he was premature. We can never
do enough to thank the NHS and everyone at the
John Radcliffe Hospital in Oxford. Our lives are ritual with
Ethan in them.

Speaker 1 (17:46):
Around the world and over centuries, the placenta has held
and continues to hold deep meaning. Some cultures revere it,
honoring it with a special burial. Mummified placentas have been
found in ancient Egyptian two ms. You know I would
get back to ancient Egypt again and others consume it

(18:06):
and recognition of its power. It's been used in beauty
products preserved in a jar to ensure good health. It
is varyingly seen as an older sibling, a twin part
of the baby itself, a friend, the finest jacket. This
reverence is not unwarranted. The placenta, at its core, represents
the fundamental vital connection between a mother and developing fetus,

(18:31):
a physical, metabolic, and immunologic bond. It's the first organ
you make and the first you say goodbye to.

Speaker 5 (18:40):
That feels so profound.

Speaker 1 (18:44):
Because it is.

Speaker 5 (18:45):
Am I going to cry about it?

Speaker 1 (18:47):
I just teared up a little bit myself. I've read
this over this a million times.

Speaker 5 (18:51):
Yeah, but wow, aronkay.

Speaker 1 (18:54):
It's the only organ ever connected to another individual. It
filters waste, it transfers vital nutrients, and acts as an
important immunological barrier between mother and fetus. It's remarkable.

Speaker 4 (19:07):
I also, I have shared before how much I love
the uterus. Yeah, and I still feel that way. Like
I feel so. I have my earrings on today. I
love thank you their gift from you.

Speaker 1 (19:20):
Congrats to myself for the good gift.

Speaker 4 (19:23):
I especially doing this research, and I haven't even learned
what you're going to teach me yet. But I love
the placenta, I know so much.

Speaker 1 (19:36):
Yeah, you know, and I think it had always been
just a secondary character what in your life story or
in my life story, in the story that I imagine, you know.
And I don't even know if I had a good
idea of what a placenta looks like. Yeah, so Aaron,
would you mind?

Speaker 4 (19:54):
Do you want to see I would like to see
I have today with us here today bottle of a
plas not a placenta. Thank you to UCSC Family Medicine
Department for letting me borrow this.

Speaker 5 (20:08):
Shout out.

Speaker 1 (20:08):
Yeah, I mean that's that's basically it.

Speaker 5 (20:10):
It is round, it's discoyed. It's discoyed.

Speaker 4 (20:14):
It has vessels on one side that is connected to
the baby by a numbilical cord, and then on the
other side where it was connected to the uterus. It
usually is more rough and bumpy. That's why this one
is like that.

Speaker 1 (20:24):
Yeah, I think it's it's bigger than than I think.
A lot of people think it's better that bigger than
I thought.

Speaker 5 (20:30):
Yeah it would be, and some of them are hefty.

Speaker 1 (20:32):
Oh yeah, I was looking at pictures and I was just.

Speaker 5 (20:35):
I don't know if I should leave this blown away
or that's up to you. Keep it here there for
the vibes.

Speaker 1 (20:41):
But yeah it is good. Yeah we can. We can
honor the placenta here. Yeah, but yeah it is. It
is a remarkable organ it really is. And I really want,
if nothing else, just for us to think more about
the placenta, like going forward. Anyone who's listening, okay, because
the placenta deserves this recognition. At the same time, the

(21:03):
placenta is also at the root of some of the
most common disorders of pregnancy, such as preclamsia. It can
invade into the uterine wall too deeply, not deeply enough,
or in a problematic spot. It can separate too early
or not separate when it should, and the placenta acting
in these unexpected ways can lead to potentially harmful or

(21:25):
even deadly consequences for both fetus and pregnant person. As
I'm always saying on this podcast, life is full of
trade offs, and the placenta is no exception. The intimacy
formed by this connection is necessary for fetal growth and development,
but it can also leave both mother and fetus vulnerable
when things go wrong. Despite this potentially high cost, the

(21:49):
placenta is a widespread feature of mammals, and it has
evolved in many other classes of animals. The how and
why of that evolutionary story is what I'm going to
talk about today. So exciting from the human placenta's ancient origins,
to the diversity we see in the placentas of present
day mammals, from the role viruses may have played in

(22:10):
its development, to some of the trade offs that we
humans face when it comes to our invasive placentas, and
also what I mean by invasive. I'll get into it.
My overall goal is to get us to think about
why the placenta as opposed to other reproductive strategies like
egg laying, and why the human placenta as opposed to
other mammalian placentas, like why why these things? How did

(22:31):
we get here? Before I dig in, I want to
mention a couple of things upfront. The first is that
I'll be talking about the placenta in terms of what
it is expected to do throughout a pregnancy, which does
not capture the incredible variation that can occur between individuals,
or even within one individual. Pregnancy. Yeah, nor will I
be exploring the multitude of things that can happen when

(22:53):
the placenta acts Outside of that. We could do an
entire episode on each placental disorder. We really really could.
The other thing is that this is not a comprehensive
review of the placenta in all of its dimensions, like
the cultural importance, the history of its study, its physiology,
and so on. It's just a quick tour through one
of the coolest organs. But fortunately there are many sources

(23:17):
where you can get that more detailed info, and we'll
be posting those on our website. Okay, okay, you know
that I love to start deep.

Speaker 5 (23:26):
How deep are we going to go?

Speaker 1 (23:28):
It's pretty deep. Before the dinosaurs life on Earth began
in the water.

Speaker 5 (23:34):
I love it when you do this, I really doh
my gosh.

Speaker 1 (23:39):
Ok And there it remained for hundreds of millions of years.
We're going pretty deep.

Speaker 5 (23:44):
I love it.

Speaker 1 (23:44):
Around three hundred and fifty to four hundred million years ago,
a group of four legged animals made their way onto land.
This group is the ancestor of all vertebrates except for fish,
so it includes humans right not fish. These first the
land dwelling animals couldn't quite shake their aquatic roots, and
so they continued to keep laying their unfertilized eggs in water,

(24:06):
where a male would later come by and fertilize them.
This water aspect of these eggs, it's not a preference,
it was a necessity. Without it, the eggs would dry out.
But this reliance on water was limiting, so some of
these animals evolved another strategy, eggs covered with a more
protective coating, which meant that they could last outside of water,

(24:27):
which then enabled these animals to further explore land and
go out deeper and deeper into land. But this coating
made the eggs less permeable, which meant that fertilization had
to happen internally, acquired a whole new set of things
before the egg and the yulk had fully formed. Okay, yep, yeah,

(24:48):
And then that was in contrast to externally, like the
way that frogs will lay.

Speaker 4 (24:52):
Eggs in or like a lot of fish, a lot
of fish, right exactly.

Speaker 1 (24:56):
And so then after fertilization internally and after the yolk
and egg had formed, the female would then lay her
eggs and wait for them to hatch like a crocodile, right, right.

Speaker 4 (25:07):
Not the first egg laying animal that I think of,
by the way, but I love that that for example.

Speaker 1 (25:11):
What is the first one? A bird?

Speaker 3 (25:13):
Yeah?

Speaker 1 (25:13):
But like, yeah, I mean it's true, I think of crocodiles.
I love that were turtles.

Speaker 5 (25:20):
I don't often think about crocodile reproduction. I think that's
what it is.

Speaker 6 (25:24):
You.

Speaker 1 (25:24):
Oh, but you think often about bird reproduction.

Speaker 4 (25:26):
Well, I eat eggs, so, oh egg like that's mine.

Speaker 1 (25:30):
Yeah, I guess I don't eat crocodile eggs.

Speaker 5 (25:32):
But I just.

Speaker 1 (25:34):
Also, that's so funny because when you said bird, I
pictured like robins, not chickens, which is the most Oh
my god, I love it.

Speaker 4 (25:41):
Okay, so crocodiles, crocodiles la eggs and so.

Speaker 1 (25:45):
But the time window between internal fertilization and egg laying,
so like when those eggs were fertilized and formed and
then when they were actually like deposited, right, was variable.
If you kept your eggs inside longer, it meant that
you could more closely control the temperature and humidity that
these eggs were exposed to, which could increase the chances

(26:06):
that your offspring survived. Okay, Eggs can be quite vulnerable
to environmental threats, predators, weather extremes, fungal pathogens, and so
some animals took this one step further, keeping the eggs
inside until they were ready to hatch. Okay, one major
transition remained though, How did the embryo get its nutrients?

(26:26):
How did that embryo inside the eggs? So egg layers
provided nutrients through the yolk encased in that less permeable barrier.
But the thing is you were limited. So like when
that egg was formed, that yolk it was usually going
to deplete until that's all you have. It's all you have.

Speaker 4 (26:43):
The embryo has to be able to survive and develop
enough with just whatever is in that yolk.

Speaker 1 (26:47):
Yeah, it's like meal prepping essentially.

Speaker 5 (26:56):
Yeah, it's exactly.

Speaker 1 (26:56):
That's exactly like prepping.

Speaker 5 (27:00):
I love it.

Speaker 1 (27:00):
Okay, Okay, there you go. See. But then what if
you didn't want a meal prep and you're like this
is not enough food. I'm yeah. Later in the week
and you're like I'm starving. Yeah yeah, So what if
instead you could provide nutrients to the embryo directly and continuously.

Speaker 4 (27:16):
Continuous throughout pregnant. You could make your meals on the
go right, Yeah.

Speaker 1 (27:19):
You could always have like a resource. Oh well, just
there's a little snack drawer.

Speaker 5 (27:22):
Snack drawer.

Speaker 1 (27:23):
Yeah, I don't know, these metaphors might not work. I
really like we can. We can reel it back in.
And so a subset of these egg laying animals evolved
the ability to pass nutrients directly to the developing embryo,
not via a yolk, but through an organ that connected
mother to embryo, an organ that we know as the placenta.

(27:46):
So we went from laying unfertilized eggs and water, to
laying fertilized eggs on land, to retaining those fertilized eggs
for longer periods of time, to then getting rid of
this eggshell that didn't let nutrients in or out to
directly connect with the fetus and remain in contact for
the duration of pregnancy.

Speaker 5 (28:05):
Okay, that's how we got boom boom boom to the placenta, straightforward, honestly, right.

Speaker 1 (28:09):
Okay, it's an oversimplification, of course, it's like covering hundreds
of billions of years. And I also don't want to
with this, you know, with this explanation give off the
impression that the placenta or live birth is like the
end all, be all reproductive strategy, or that it's one
unique to mammals. Like I said earlier, it evolved independently

(28:29):
in many classes of animals. And the fact that we
see so many different reproductive strategies today, like laying unfertilized eggs,
laying fertilized eggs, retaining eggs until they're ready to hatch,
life birth, and so on, the variation is endless. Yeah,
what was the one that I like texted you about
gastric brooding frogs?

Speaker 4 (28:48):
Yeah, and then I came back with the sea horses.

Speaker 1 (28:51):
Yes, yeah, I know. There are so many different ways,
so many reproductive strategy It's incredible. And this shows us
that there are pros and cons for each and that
what works for one species might not work for another.
So sure, laying eggs might make them more susceptible to
external threats, but it frees you up out running or
out flying a predator is more challenging when you're carrying

(29:12):
around a load of offspring in your uterus literally. On
the other hand, investment in offspring is generally higher than
placental mammals, which can translate into higher survival for those offspring.
I mean, we could spend hours discussing and you know,
arguing the trade offs of different reproductive strategies, but we're
not going to do it today.

Speaker 3 (29:31):
No.

Speaker 1 (29:32):
So I mentioned that the placenta evolved independently multiple times
across the animal kingdom. Yeah, what in mammals though it
happened just once?

Speaker 9 (29:39):
Ok.

Speaker 1 (29:40):
I gotta talk about the mammals.

Speaker 5 (29:41):
Okay, Now I really want to know about the other ones. Interesting.

Speaker 1 (29:43):
You know, I can send you some sources. Can go
to our website, this podcast with you dot com, go
to the sources tet. But this means that the incredible
placental diversity that we see in mammals today comes from
just one origin. Wow, around two hundred and fifty million
years go. We still have to go far back. A
group of animals called the thrapsids split off from the rest.

(30:05):
And these were reptile like creatures, and they differed from
the rest in three key ways. First, they could generate
their own body heat and maintain temperature crucial. Second, they
had body hair, which helped provide insulation for heat maintenance.
And third they developed the ability to produce milk. Oh.

Speaker 5 (30:26):
Interesting, I know, I didn't know it went that far
back either.

Speaker 8 (30:30):
Yeah, Okay.

Speaker 1 (30:31):
Over the next one hundred million years or so, this
group continued to diversify, splitting off into the three main
groups that today make up modern mammals. We've got the monitories,
the egg laying mammals like the platypus and the Echidna
love them. We've got the marsupials, the one who use
a pouch and birth teeny tiny young like the Tasmanian devil, kangaroo, Koala,
etct some of my faves. And then the Eutherians or

(30:53):
the placental mammals, which includes all other mammals today, including humans.
I have to throw in this way actually because it
just it bothered me as I read this, and it's
probably old news to people who know more about the placenta.
But marsupials also possess structures resembling a placenta. They just
play a slightly different role and are very different than
our placentas. And so one key difference between marsupials and

(31:16):
Eutherians is when nutrient transfer takes place. So in marsupials
it mostly takes place during lactation, while in Eutherians most
nutrient transfer happens during gestation.

Speaker 5 (31:26):
Got it right, I think I understand.

Speaker 4 (31:29):
Yeah, so they have something that's like a placenta, but
its main role is not.

Speaker 1 (31:33):
Provided, not threading the nutrients. Yeah, yeah, makes sense. But
it's like, but we still call the Eutherian mammals the placentals, okay,
And I'm just like, well, actually, yeah, I know it's
my I can't resist. But what I wanted to say
about lactation was that in monotremes they don't have nipples.
They have like little pores. Yes, I knew that, and
they like the little the little babies lap up. I know,

(31:56):
it's so so amazing.

Speaker 5 (31:58):
I know I want to ask more about I won't though.

Speaker 1 (32:02):
You get to ask me, and I'll just say I
don't know.

Speaker 5 (32:04):
Well, I don't know how to form my question.

Speaker 4 (32:06):
Okay, problem because it's like going back to like those
early early early apps, the thrapcids, like you know, dimetrodon
Yeah was that a thrapsid or was that something? See
it's only because I'm thinking of like our all of
the dinosaur toys that we have at home, and I
always go, well, this one's not right.

Speaker 1 (32:22):
Which ones are therapids? In which ones or something like that.

Speaker 6 (32:26):
Yeah.

Speaker 1 (32:26):
See, and this is where.

Speaker 4 (32:27):
My anyways, Yeah, I might did evo bio off topic,
off topic.

Speaker 1 (32:33):
Well, well we'll bring it back to the placenta.

Speaker 5 (32:35):
That's please.

Speaker 1 (32:35):
Okay. So, so these earliest Eutherian placenta having mammals probably
emerged around one hundred and ten to one hundred and
twenty five million years ago. Okay, Yeah, and from there
nature did its thing. Evolution did its thing. The asteroid
that caused a massed extinction event sixty six million years
ago did its thing. Cleared the way for the age

(32:56):
of mammals. Check out our blast of Mycosest episode for more,
so much more, and the placenta diversified. When it comes
to Eutherian placentas, there's a whole lot of variation from
size to shape to invasiveness. You know, we held up
the human placenta, which is like a discoid shape. They
come in all different shapes. It's amazing. One book I

(33:19):
read suggested that it is probably the most variable of
all mammalian organs.

Speaker 5 (33:24):
Really yeah, that's interesting.

Speaker 1 (33:25):
I mean I wonder if every organ researcher says the
same thing about their.

Speaker 5 (33:29):
Organ, like my organ is actually the cold.

Speaker 1 (33:31):
Blood is the most divert.

Speaker 5 (33:33):
Sure it's not that one.

Speaker 1 (33:36):
We'll do an episode on okay, but for today, I'm
only going to get into one dimension of this variation
in mammalian placentas, and that is in the invasiveness right
of the placenta. So you can look at invasiveness in
two ways. One is in the number of cell layers
separating fetal and maternal bloodstreams, and the second is in
how physically deeply fetal tissue invades and restructures maternal tissue.

(34:00):
So one is like how many layers are in between,
and the other is.

Speaker 5 (34:02):
Like, how how deep do those villa I go?

Speaker 1 (34:04):
Exactly? Yeah. Researchers generally group the invasiveness of the placenta
into three categories. Sometimes there's a fourth one added depending
on the number of cellular layers. So on the less
invasive side of things, we've got like pigs, sheep, dolphin, hippo.
In the medium invasive, we've got dogs, sloths, elephants, ardvarks, raccoons.

(34:27):
And on the maximally invasive, Yeah.

Speaker 5 (34:29):
That was like a really wide range.

Speaker 1 (34:31):
Well that's okay, yeah, yeah, okay, in a second, kap.
On the maximally invasive, as in the placental tissue is
often referred to as being bathed in maternal blood. Right,
We've got humans and other great apes, mice, rabbits, guinea pigs,
nine banded armadillos, hyenas, and others.

Speaker 4 (34:50):
Okay, that's also more than I realized. Yeah, that are
like that considered that invasive.

Speaker 1 (34:56):
Yeah, on the invasive side of yeah, like in terms
of the cell layers. Yeah, And so unless I specify otherwise,
when I'm talking about invasiveness, I'm usually referring to this
classification based on cell layers between fetal and maternal blood.
Why is there such variation? Is there a benefit to
one type of placenta over another?

Speaker 5 (35:17):
I mean, yes, well, yes, or trade offs? Yeah, yeah, I.

Speaker 1 (35:22):
Mean, and it's it's a great we don't fully know
the answer class classic, and it doesn't seem to be
driven solely by like how related like different animal groups
and like, oh well all of the you know, there
are some broad trends, but for the most part, it
doesn't really seem that way.

Speaker 4 (35:41):
So it's like a bunch of examples of convergent evolution essentially.

Speaker 1 (35:45):
Friend of like what is driving in different species? We
don't fully understand.

Speaker 5 (35:49):
I think the drivers for interesting for that.

Speaker 1 (35:51):
Yeah, but one thing that we do know is that
our invasive placenta, like the human invasive placenta, is the
type that probably evolved first, and then it evolved to
become less invasive.

Speaker 5 (36:05):
Interesting.

Speaker 1 (36:06):
Interesting. Indeed, Okay, it's possible that, like so we're talking
about trade offs, it's possible that certain molecules like iron
have a slightly more difficult time getting to the fetus
in mammals with less invasive placentas. But that's not entirely clear.
And another hypothesis is that the more invasive the placenta,
the better the signaling in all directions like mom to fetus,

(36:28):
fetus to mom, placenta to mom, et cetera. I also
read that placental transfer of certain antibodies IgG if you're curious,
which is the most abundant in our blood, has only
been observed in invasive placentas, possibly demonstrating active transport of
this antibody to the fetus, which could have then like
protective roles.

Speaker 4 (36:48):
Right, because then your fetus is basically your baby's being
born with all of the antibodies that mom has had. Yeah,
so like protection from all protections at least passively, at
least for those first few months.

Speaker 1 (36:58):
Right, which question mark? Okay is not fully clear?

Speaker 5 (37:02):
Yeah, okay?

Speaker 1 (37:04):
Why still, why do we have this invasive placenta? One
popular but now largely discarded hypothesis is that our invasive
placentas were necessary to get enough nutrients to the developing
human fetal brain. For one, our big brains came after
this invasive.

Speaker 4 (37:20):
Clearly, if this was the first type first time, well
it wasn't always known that that was the case.

Speaker 5 (37:25):
Right, that makes sense.

Speaker 1 (37:26):
But two, not all animals with invasive placentas have big brains,
and not all animals with big brains have invasive placentas,
like dolphins, which have among the least invasive type of placenta.
And four, there is no evidence that transfer of nutrients
is somehow greater or more efficient and more invasive placentas
compared to less invasive books.

Speaker 5 (37:47):
Okay, all right.

Speaker 1 (37:49):
The idea that invasive placentas were necessary for our big
brains was based on this arrogant assumption that whatever placenta
we humans have must be the most advanced and the
least primitive. It's the best, it's the best. But since
that's not the case, we may have to consider instead
two related questions, what are the potential downsides to an
invasive placenta and how have those of us with invasive

(38:11):
placentas adapted to deal with those downsides. So let's start
with one of the major potential drawbacks, the fact that
during pregnancy there is an alien thing growing inside you. Yes, yes,
it's fifty percent you, but only fifty percent, but only
fifty percent. That other fifty percent is not you, not
you over the past five hundred million years, which is

(38:33):
when the first natural killer cells are thought to have evolved.

Speaker 5 (38:36):
Oh my god, wow, Okay, I know, wow.

Speaker 9 (38:38):
I know.

Speaker 1 (38:39):
That shows how fundamental this idea is.

Speaker 4 (38:42):
And like just immunology of needing to be able to
find non self.

Speaker 1 (38:48):
That is the whole point of the immune system is
distinguishing self and non self. Like that is pretty much
the point of any I mean, and it's that's an oversimplification, sure,
but pretty much at its core, y versus self. Yeah,
And so sometimes our immune system works a little better
than we want it to, like when we reject a

(39:08):
transplanted organ. Sometimes it's a little overzealous and it blurs
the line between self and non self. Is in the
case of autoimmune diseases, and sometimes it might need a
little help, but overall, this ability is so crucial to
our survival that it's a universal feature in all multicellular
life on this planet and has been for quite some time.

(39:30):
And so pregnancy then should offer a pretty huge immunological challenge. Right,
there's this non self thing inside that has.

Speaker 4 (39:37):
To stay there for however many months, depending on what
species you are, right, two hundred and sixty six days
at least, there are yeah, yeah.

Speaker 1 (39:45):
Yep, yeah yeah, And so from an immunological standpoint, our
bodies should flag the newly implanted blasticist and mount a
defense against it. Sometimes this is what happens. And one
potential downside of our invasive placentas is that the deep
for the invasion, the higher the risk for triggering an
immune response from the mother. Right, Many species that have

(40:06):
similarly invasive placentas like ours tend to have much shorter gestations,
in part potentially to minimize this risk, but we seem
to manage overall.

Speaker 4 (40:16):
Right, This is though, why we see things like recist disease, right,
where you have at least some fetal cells that are
able to cross over this barrier and come onto the
other side of our cells, and then we do see
those and mount a defense against them in a future pregnancy.

Speaker 1 (40:34):
Potentially with and with potentially really.

Speaker 4 (40:36):
Really disastrous consequences. Exactly exactly, yeah.

Speaker 5 (40:39):
Yeah, yeah.

Speaker 1 (40:40):
And so there is like this immune relationship that is
really complex.

Speaker 5 (40:45):
It's a very tight rope that we are walking.

Speaker 1 (40:47):
Yep, yeah, yeah. So what like how like why what
allows for tolerance over rejection?

Speaker 6 (40:56):
Yeah?

Speaker 1 (40:56):
One thing that helps is that a fetus is not
the same as an organ transplant. A transplanted organ is
connected to the recipient's blood supply, whereas during pregnancy, the
fetal and maternal blood are kept separate, right, and they
are kept separate by the outer layer of the placenta.
And this outer layer consists of a bunch of cells

(41:17):
that are fused together to make a tissue. So it's
not like individual cells anymore. The membranes have been fused
together to create like one giant cell with like multinucleated cell.

Speaker 4 (41:26):
That's why they call it a sensicio trophoblasts. If you
remember our RSV episode, that stands for respiratories and social virus.

Speaker 5 (41:33):
I'm going nerdy, I'm so sorry, but sensisium. Yeah, multinucleated cell.

Speaker 1 (41:38):
Multinucleated cells, so it's just like one cell, but it's
a long, giant cell.

Speaker 4 (41:43):
It goes the whole entire outside of that lastosis.

Speaker 1 (41:46):
Yep. And this tissue is pretty impenetrable because these cells
are fused together. There are no more membranes between the cells,
which means there aren't any gaps to let in let's say,
for example, mom's antibodies, which might flag the fetus as
non self. So it just creates this like there are
no gaps, right, you can't you can't even get no
foot in the door.

Speaker 4 (42:06):
No maternal stuff can get in to the placenta at
that point.

Speaker 6 (42:10):
Yeah.

Speaker 1 (42:11):
Yeah, And this is a pretty crucial tissue and its
role is not limited to barrier right. It's also a
hugely important regulator in the expression of hormones like upregulate
that hormone, down regulate that hormone, proteins and other molecules
that are used in communication between placenta and mom. And
we owe it all to an ancient virus stop it

(42:33):
oh yeah what?

Speaker 5 (42:35):
Oh yeah.

Speaker 1 (42:36):
At some point one of our ancestors was infected with
a retrovirus which inserted its genetic material into one of
their sperm or egg cells.

Speaker 5 (42:46):
Okay, okay.

Speaker 1 (42:48):
When those cells replicated, like when they formed an embryo
and someone so did, the viral DNA carried it with it, okay,
which was then also passed down to subsequent generations because
it would have been an all all of the germ
cells down the line. Over time, we lost bits of
that viral DNA, but some crucial parts remained, genes that

(43:08):
maybe we were like, huh, this seems like it could
be worth keeping around. We call these viral remnants in
general endogenous retroviruses, and our genome is chock full of them.
I think I've talked about this before on the podcast
being really excited. About five to eight percent of the
human genome is a viral origin. Five to eight percent.

(43:29):
That's a huge proportions. Not us virus, I mean, it
is us the genes since it in one and since
it in two, which help us to fuse these cells
together to make that like one layer, and also help
us escape detection from mom. They come from a couple

(43:51):
of these ancient viruses. That's what allows for that that
formation of tissue, that barrier.

Speaker 8 (43:59):
Yeah.

Speaker 4 (43:59):
Really, really, these genes these viral genes. Essentially, these genes
that are viral in origin.

Speaker 1 (44:04):
Yeah, wow it and one since it in two. Without
these ancient viral infections, we would not be able to
form the super important tissue. We wouldn't be here.

Speaker 5 (44:13):
Wow.

Speaker 1 (44:13):
Yeah. And what's amazing about these indogenous retroviruses, these since
sittant genes, is that they appear across eutherean mammals, but
not from just one infection event. Mammals have been infected
over and over again with different viruses that have found
their way into our genomes and have been co opted

(44:36):
into helping us build this tissue layer.

Speaker 8 (44:38):
Wow.

Speaker 9 (44:39):
Wow.

Speaker 5 (44:41):
I know I'm being mind blown right now.

Speaker 1 (44:44):
I say I'm read being mind blown, and I've.

Speaker 5 (44:48):
Wrote that, I wrote this, and it's still blowing my mind.

Speaker 1 (44:52):
But the immunological relationship between mother and fetus isn't just
one of avoiding detection or building barriers, right. The activation
of the maternal immune system is actually a necessary part
of pregnancy, and instead of that activation leading to a
destructive response, it leads to a regulatory or protective one,

(45:13):
one in which acceptance of the embryo is initiated. The
portrayal of pregnancy as immunosuppressive isn't accurate. In fact, the
mother is very aware. The mother's immune system is very
aware of this new non self thing growing. And it's
more that the maternal immunological self is modified a change

(45:33):
in immune tolerance. As a side note, this shift in
self might help to explain why some people with autoimmune
diseases experienced symptoms lessening pregnancy. Yeah, but there may be
a cost to this tolerance. Recent research has investigated whether
our invasive placenta us, which require more immune tolerance than
less invasive ones, may have made us more vulnerable to

(45:55):
cancer as a species.

Speaker 5 (45:57):
Really really, I did not know this connection.

Speaker 1 (46:00):
Yeah, okay, it's been like I think, in the past
ten ish years or so, there's been a lot more
interest in this aspect of the immunological side of placentas
interest and placentation.

Speaker 5 (46:09):
Yeah okay.

Speaker 1 (46:10):
In fact, many researchers have noted the similarities between cancer
and placentation. The formation of the placenta very interesting. There
is immune evasion, proliferation, invasion into other tissue and blood
vessel remodeling.

Speaker 6 (46:26):
Wow.

Speaker 4 (46:27):
Yeah, I know, and it's like self, but not because
it's abnormal cell division.

Speaker 6 (46:35):
Ooh.

Speaker 1 (46:36):
Interesting yep, And studies that have compared cancer rates across
mammals have found that cancer tends to be higher in
species that have more invasive placentas, like humans, compared to
ones that don't, like cows. And I'm sure like that
other things play a role, you know, lifespan, body, seze.
It's never one thing. Yeah, yeah, but the pattern isn't

(46:59):
cut and dry. Where is it clear how cancer and
invasive placentation might be related mechanistically. It's a fascinating area
for future study though, especially what it might be able
to tell us about our individual responses to invasive placentation. Yeah,
because wow, there is a range of responses. So, like

(47:19):
we talked about, the placenta is more than just a
gateway for communication between mother and fetus. It's also the
place where we see maternal, fetal and paternal needs expressed.
From the fetus's perspective, more is better, more resources, more nutrients,
more everything to help you grow.

Speaker 5 (47:37):
Sometimes and we'll get there, not always.

Speaker 1 (47:40):
Not always. But also from mom's point of view, you
also want fetus to grow, but you can't give away
all of your resources since that would impact your ability
to care for the fetus later in pregnancy after birth,
in future pregnancies, and also for existing offspring. And so
these needs might be in immediate conflict, but there seems

(48:01):
to me to be an ultimate shared goal for the two, right,
a healthy newborn while also not draining mom to the
point where postpartum care is impossible.

Speaker 5 (48:11):
Right, A little balance, a little balance.

Speaker 1 (48:12):
It's like, I think a lot of people refer to
it as maternal fetal conflict, which is a whole separate thing,
and there are a lot of dimensions to that, and
there's like also the social sociology and political side and
legal side of that. But I have been thinking of
it as like a maternal fetal conversation.

Speaker 8 (48:29):
Right.

Speaker 1 (48:29):
Yeah, it's a balance, a balance, it's a dance, a balance,
and that balance is not always struck. Sometimes, for instance,
the placenta invades too deeply into the uterine wall, past
the dissidua, which can cause hemorrhage or perforation of the uterus.
Or sometimes it doesn't invade deeply enough, and maybe this
is because our immune system prevents it. This incomplete invasion

(48:53):
is thought to be at the root of pre eclampsia.
We don't know the precise mechanism or if preeclamsia has
one root cause or multiple, is it a syndrome or
is it well one? Yeah.

Speaker 4 (49:06):
Well, also I'll talk more about like the different types
of preeclampsia, whether it's early term, whether it's term, whether
it's postpartum preeclamsia.

Speaker 5 (49:13):
Are they different, are they the same.

Speaker 1 (49:16):
It's the same pathway that's getting us to these things,
or multiple pathways? Yeah, yeah. But one idea for preeclamsia
is that the placenta doesn't invade deeply enough, which can
limit the blood supply to the placenta and fetus. Initially,
in earlier in pregnancy, that's not a problem since the
fetus actually needs a low oxygen environment to develop. But

(49:36):
as pregnancy progresses, oxygen demands increase, and if that initial
invasion wasn't deep enough, if those arteries weren't remodeled enough,
that can mean that the fetus is getting low or
intermittently low oxygen. And so then mom senses this or
through the placenta is told this, and then her blood
pressure will spike to compensate, But that doesn't always solve

(50:00):
the problem, and so then things can kind of get
increasingly out of balance, and then there can be a
lot of danger, right that happens. Yeah, Aaron, I know
that You'll get into more of the details later on.
But one of the things that I find fascinating about
preeclampsia relates back to this idea that invasive placentas might
be related to higher rates of cancer. If pre eclampsia

(50:24):
has an immunological component, and if mother's immune system is
preventing deep invasion of the placenta, might cancer rates be
lower in people who have had pre eclampsia. Huh, I
don't like so first of all that now I'm like, not,
we're wondering.

Speaker 5 (50:40):
You are wondering.

Speaker 1 (50:41):
Yeah, I'm not saying like, and here's there's been reviews
about this and meta analyzes. I did look up a
few large studies and a meta analysis that did suggest
that people who have had preeclamsia are overall less likely
to develop breast cancer. Interesting, but there's like, there's so
much more to that story or so many factors. How

(51:01):
protective might pre acclamcia be. What's the mechanism of protection
if there is one? Is this a causal connection or
just you know, a correlation. And the same can be
said for the placenta. Like, there's so so much more
to the story. This was really just a brief or
at least as brief as.

Speaker 5 (51:18):
I could make it could keep going and keep listening
to you.

Speaker 1 (51:23):
Just a brief tour through the evolutionary history of one
of the most fascinating mammalian organs out there. And I
hope that even if you don't remember any one thing
from this story, you at least find yourself thinking more
about the placenta.

Speaker 5 (51:37):
The placenta that we all used to have, we all use.

Speaker 4 (51:39):
I think that's the thing that's interesting that no one
ever thinks about, Like, yeah, we all because I think
a lot about the uterus and how we all came
from a uterus, whether you have one or not, right,
you came from.

Speaker 5 (51:50):
One, which is so interesting.

Speaker 4 (51:52):
But then like we all, I never thought about the
fact that, like, we all had at a.

Speaker 5 (51:57):
Placenta and we all no longer do.

Speaker 1 (52:00):
Yeah, unless unless you kept yours.

Speaker 4 (52:03):
Yeah, but then that's not yours. That was your fetuses.
That was your baby's placenta.

Speaker 1 (52:08):
But if you, if someone, if you, if you kind
of kept your.

Speaker 4 (52:11):
Oh that's interesting thought about that. Yeah, Okay, so some
people have their I.

Speaker 1 (52:16):
Mean yeah, it's no longer attached to us. Yeah, it's
no longer it doesn't serve using.

Speaker 4 (52:20):
The function that after birth, it stops serving its function.
I mean, it's just so interesting and it's huge.

Speaker 1 (52:26):
Yeah, it's like that takes a lot of resources.

Speaker 5 (52:29):
Oh my gosh.

Speaker 4 (52:29):
Yes, yeah, it's hefty. It's a hefty organ and you
can tell when they're not hefty. Oh interesting, Yeah, like
I I mean, you see a whole variety of placentas
when you've been delivering babies. I haven't done a lot
of but seen a lot of fairy number and there
they range for sure.

Speaker 1 (52:43):
Which is amazing and interesting.

Speaker 8 (52:46):
I know, I know.

Speaker 1 (52:47):
Okay, we I mean we could we could keep talking
about yeah. Yeah, but yeah no, that's I mean that
and that basically is the placenta story. You know, let's
think about viruses, Let's think about what the placenta allows
us to do from what a journey we mede a
logical standpoint, it's incredible. Yeah, so yeah, let's keep going
with the journey. Aaron, tell me what's going on with
your body and pregnancy?

Speaker 4 (53:08):
Okay, I literally can't wait to take We'll take a
quick break and then we'll get into it.

Speaker 10 (53:28):
During both of my pregnancies, I experienced intrahabatic colostasis of pregnancy.
This is a rare complication where your liver cannot process
aile salts and acids, so those begin to accumulate in
your blood. This causes itchy, which is mainly focused on
the palms of your hands and soles of your feet.
It was the worst age I have ever experienced. It

(53:49):
was not a dangerous complication for me as a pregnant person,
but it was extremely dangerous for the fetus. Mortality rate
in utero is very high. That is why I have
to be monitored very closely up until thirty seven weeks
when I was used both times. During both of my pregnancies,
I had to go to the hospital every few days
to have a CTG taken. They did numerous ultrasounds and

(54:13):
I was even hospitalized the first time around. They also
prescribed urso, the oxygalic acid, which helped a lot with
lowering bile salts and acids. Itchiness also went away after that.
The last ten weeks of my pregnancies were very stressful,
and looking back, I am amazed that I would call
I managed to stay. Both of my kids were born

(54:35):
healthy at thirty seven weeks after induction. Chances of getting
intracapathic colostasis of pregnancy with every subsequent pregnancy are higher
if you have had it before. Two was enough for
me that feeling of unbearable itchiness will always stay with me.

Speaker 9 (54:53):
My name is Sarah, she heard thirty six year old
female mother to an awesome daughter. I had a positive
home pregnancy tests on Christmas Day twenty twenty two. I
was thirty four years old at the time. We were
very lucky to conceive on our very first try. We
had our confirmation ultrasound in eight weeks, and as I

(55:13):
progressed towards the second dry master, I felt my mental
health spiraling. In addition to all of the other common
pregnancy side effects like morning sickness and fatigue, my anxiety
started to worsen to the point of panic attacks. My
body was changing in a million ways, and I had
no control over any of it, let alone any peace

(55:34):
of mind to assure me the baby was okay, or
how to judge what was normal. I started to feel
like maybe my medical background was not an advantage in
this situation, because I knew too much when I brought
my fears up to my OB. I felt dismissed. Each
visit was short about five minutes. They checked the fetal
heartbeat and sent me on my way. Even though this

(55:56):
was my first pregnancy, I took it upon myself to
research pregnancy mental health and found mostly postpartum articles. I
eventually talked to my PCP, who started me on lexipro
and busbar. I was referred to a mental health provider,
and over the remaining six months of my pregnancy, I
had weekly video calls with an LCSW. She helped me

(56:21):
develop coping strategies for my anxiety and guided me in
conversations with my OB and my husband. I made affirmation journals,
mantras to recite, and fell asleep listening to guided hypno
birthing podcasts, all of which eventually helped me to overcome
my anxieties about giving birth. I had to learn how

(56:44):
to be the patient, not to provide her, and to
have faith in my husband, family, and healthcare team to
take care of me. By all accounts, I had a
very normal pregnancy and easy birth. At the pediatrician visits
with my daughter, I filled out mood questionnaires at every
visit to screen for postpartum depression, which thankfully I didn't develop,

(57:05):
but it did make me wonder why aren't these types
of questionnaires available throughout the entire pregnancy.

Speaker 4 (57:37):
So I left off the biology last week kind of
at the start of the second trimester. But in that
episode I mostly was talking about the embryo and the
invasion and the thing and etc. But in this episode,
I'm going to focus on the pregnancy and the pregnant
person and not the fetus. Okay, because as incredible and

(57:59):
awesome as the process of fetal development is, like, it
only happens inside of a uterus, and so like the
changes that are required in our bodies in order for
a pregnancy to actually continue to term, Like, that's where.

Speaker 5 (58:12):
I'm that's where the money is for me, right now. Okay,
someday we'll do fiddel development because it's really cool too.

Speaker 8 (58:17):
Yeah.

Speaker 4 (58:18):
Okay, So we're going to actually take steps backwards to
the beginning of the pregnancy, okay, kind of, We're going
to go back to fertilization, Okay. Yeah, So that we
will recall from last week, is about two weeks after
your last menstrual cycle, right, is when you ovulate and

(58:38):
then you get fertilized, okay, and then about six days
after that is when we have implantation that starts. So
we're about day.

Speaker 5 (58:46):
Twenty one ish of our menstrual cycle.

Speaker 1 (58:48):
Okay.

Speaker 4 (58:49):
By about this time, and then like the next week after,
when you may have missed a period and may have
had that positive pregnancy test, all ready your own physiology
has changed dramatically because of the way that embryo has
embedded itself into the wall of your uterus, Like you

(59:10):
just walked us through and started secreting hormones that are
going to cause our body to change in ways that
it really only changes in the context of pregnancy. I
get really excited, And what I'm going to do for
this episode is go through these changes, not week by
week like you might see on all of the websites,
like your body is doing this this week.

Speaker 7 (59:32):
No.

Speaker 4 (59:32):
No, We're going to go body system by body system
and explain why we see maybe some of the like
weird or uncomfortable symptoms that you might experience, and why
we are susceptible to some of the complications that then
arise because of these changes in our physiology. Okay, I'm
going a rapid fire through it, but stop me at anytime. Okay,

(59:53):
We're going to start with our cardiovascular system because it's
one of the most important and one of my favorites.
One of the first changes that we see is in
our blood vessels. So because of the increased levels of
progesterone and other hormones like estrogen and prostaglandins, we see
a dilation or a widening of our blood vessels. And
what this does is decrease the resistance to flow of

(01:00:14):
fluid because of physics. Yeah, and so right away you
can start to see weird symptoms because this vasodilation can
cause edema or swelling as these blood vessels, as they
get wider, become a little bit more leaky. So then
you get fluid that can go out through the blood
vessels and into places like our ankles.

Speaker 1 (01:00:34):
And this is like a body anywhere, your whole body.

Speaker 5 (01:00:37):
It could have yeah, not like extreme, but a little bit.

Speaker 1 (01:00:40):
I mean, like the blood vessel widening, yes, everywhere.

Speaker 4 (01:00:42):
Everywhere in your whole body, which also means you might
get things like nasal congestion or nose bleeds.

Speaker 5 (01:00:48):
Oh my god.

Speaker 4 (01:00:49):
Now, this vasodilation will also cause a decrease in your
blood pressure, usually early in pregnancy, which is very interesting
to then contrast with what we'll see in preeclampsia, which
is when we have higher blood pressures. Now, on top
of this change of the width of our blood vessels,
we also have an increase in our blood volume by
how much you might ask, I would by forty to

(01:01:13):
fifty percent. What uh huh, okay, tell me more about
what that means. It means that if you have I
actually meant to look up, like what your normal blood
volume is. However many leaders I don't remember, but it
is now fifty percent higher.

Speaker 5 (01:01:27):
Within a number of weeks.

Speaker 1 (01:01:29):
Okay.

Speaker 9 (01:01:30):
Uh.

Speaker 5 (01:01:31):
And it's you literally just make.

Speaker 4 (01:01:33):
More blood volume. It means your plasma Okay, we're gonna
get a more into it. Yeah, because it's your plasma
volume that's primarily increasing.

Speaker 1 (01:01:40):
Okay.

Speaker 4 (01:01:41):
And this means a few things. Number one, it means
your heart has to be able to keep up with
this increased amount of flow, and so to do that,
we actually see structural changes to your heart to allow
for an increase in cardiac output.

Speaker 1 (01:01:55):
What kind of structural changes we see?

Speaker 4 (01:01:57):
Thickening of the like wall of the left ventricle.

Speaker 5 (01:02:02):
Do you bring over the heart? Oh my god?

Speaker 4 (01:02:06):
If you have a diagram of a heart. Your left
ventricle is over here, right, and that's the aorda is
going to come out here, and this is what this
is where your blood goes to the rest of your
body from. So yeah, the left ventricle of your heart
is going to get a little bit thicker, Your overall
heart is going to get a little bit bigger. And then,
as we'll talk about later, because of the changes in
your diaphragm and the size of your thoracic cavity, it

(01:02:27):
also gets shifted.

Speaker 5 (01:02:28):
Up into the left.

Speaker 1 (01:02:29):
Interesting, I know now.

Speaker 5 (01:02:33):
Also I think you.

Speaker 1 (01:02:34):
Give that back to you.

Speaker 8 (01:02:37):
Now.

Speaker 4 (01:02:38):
Also, we will see a compensatory increase as well in
our heart rate because your overall cardiac output is a
function of both the volume and also the rate. So
we see an increase in heart rate, which I remember
seeing on my smart watch where.

Speaker 5 (01:02:52):
It was like you have a new normal. Oh interesting,
and you're like, when I.

Speaker 1 (01:02:56):
Was pregnant, how soon does that happen?

Speaker 4 (01:02:59):
So that is that a lot of these changes are
kind of gradual where they start really early, but then
it just like continues to change all the way till
the third trimester until term. Okay, for the most part. Okay,
and it's sort of an up. It's just sort of
this it's a linear well not yet not linear, I mean,
but yes, it's a kind of contained directional, you know,
for the most part. Okay, Yeah, there's probably nuance there

(01:03:21):
that I'm skipping now. I said, your blood volume increases
my fifty percent. However, your red blood cell volume, and
remember red blood cells are the ones that actually carry
oxygen to our tissues, so they're like kind of pretty important.
They also increase, but only by about twenty to thirty percent.

Speaker 1 (01:03:42):
What does this then, difference in rate increase? How does
that manifest in other parts?

Speaker 6 (01:03:47):
Like?

Speaker 8 (01:03:47):
What is that?

Speaker 1 (01:03:47):
What are the implications of that?

Speaker 5 (01:03:50):
Okay, let me tell you.

Speaker 1 (01:03:51):
Why aren't your red blood cells also increasing?

Speaker 5 (01:03:53):
They are increasing, just not to the same not to
the same degree. So what does this? What does it mean?

Speaker 4 (01:03:58):
What are the implications? Means that you have during pregnancy
a physiologic anemia and your blood is it has less viscosity,
so it can less right because you have less part
of Yeah, it can flow a little bit more easily.
It also though, means that of course you can carry
a little bit less oxygen relatively speaking, like on the
whole you're carrying more because everything is increased, but you

(01:04:21):
have this physiologic anemia. You also then have this fetus
that is going to be relying on the oxygen that
you are giving to them. So that means that you
have to become very efficient with your oxygen transport, which
is the thing I could go really too deep on,
but I won't. But what we then see during pregnancy

(01:04:41):
is an increase in this production of this compound on
our red blood cells called two three DPG. It basically
means that when you are pregnant, your body is better
at giving away that oxygen, So your red blood cells
are more efficient at offloading oxygen so that the fetus
can get access to that oxygen. Okay, it's just like easier,

(01:05:01):
it's easier to drop off exactly, Okay, exactly. Yeah, it's
so interesting. There's also like fetal hemoglobin, things that are hemoglobin.
I know, I know, it's cool, Okay, So but it
also means you set another implication. Another implication is that
in order for our bodies to keep up with this demand,
iron requirements are significantly higher in pregnancy compared to outside

(01:05:23):
of pregnancy. And that's for two reasons, one to support
the growth of the fetus who needs iron to grow,
but also to keep up with this increased red blood
cell production, and so iron deficiency anemia can develop on
top of this physiologic anemia. And so during pregnancy people
are at pretty high risk of like anemia in general
because you already have this physiologic anemia and now you

(01:05:46):
have this increased iron requirement. So if you're not getting
enough iron in your diet, then you're not able to
make enough red blood cells.

Speaker 5 (01:05:53):
Okay, makes sense, and so right.

Speaker 1 (01:05:55):
And so then what if anemia di or if this
one two punch happens, then what are some of the downstream.

Speaker 4 (01:06:01):
I mean, it can affect It can be really problematic
when we get then into delivery because in delivery you
are going to lose some degree of blood most likely,
and so that can put people at higher risk of
complications from hemorrhage or just from blood loss in general.

Speaker 5 (01:06:15):
Okay, yeah, okay, that's.

Speaker 4 (01:06:18):
Mein I mean, it can cause problems for the fetuses
all too if you were like severely deficient.

Speaker 1 (01:06:22):
And so physiologic like are there I'm sure there's a
range of physiologic anemia, like outside of iron deficient in
the area, and so is there a point at which,
just like physiologic anemia, is where it needs problematic.

Speaker 5 (01:06:33):
Yeah, exactly, I don't think so.

Speaker 4 (01:06:35):
Okay, yeah, because it's it is what is expected during pregnancy,
right right, you expect that to happen. Okay, So if
we move on from our blood vessels in our cardiovascular system,
we'll move to another vessel that's being affected kind of
is not really vessel, it's your kidneys.

Speaker 5 (01:06:49):
They're connected by tubes. Okay, it's like a vessel.

Speaker 4 (01:06:52):
You have all this extra blood, right, your kidneys are
responsible for filtering all of your blood. That's what they do,
and so your kidneys have to work a heck of
a lot harder. And during pregnancy, your kidney's enlarge and
increase their filtration rate by fifty percent, which is so
impressive and means that you're making a crap ton of
urine and you have to pee all the time, even
before there is a fetus literally crushing your bladder.

Speaker 1 (01:07:15):
That's that's something I had never I know, thought about it.

Speaker 4 (01:07:18):
And that's why even early in pregnancy people be like,
I'm peeing all the time, and it's not because of
the fetus because that thing is like a couple cells big.
It's because you're making so much more blood, and so
your kidneys are filtering all that blood, and so you're
peeing all the time, Okay, and then eventually, of course,
this fetus is going to grow large enough to crush
your bladder. And when they do, you also can get
compression of some of the tubes that lead from your

(01:07:38):
kidneys to your bladder. And then that along with the
fact that progesterone, which I talked about already, that causes
that vasodilation, progesterone also causes like a slow down of everything.
Everything's just like moving more slowly, and so your bladder
has a little bit more stasis. It's not like squeezing
out as much.

Speaker 1 (01:07:56):
Uh huh.

Speaker 4 (01:07:56):
So you can be more prone to UTIs or urine
aritract infections during pregnancy. Interesting because you, yeah, even though
you're making so much p and ping all the time,
it also just can kind of sit there a little
bit longer. And and then because of all of these
things that are happening with like compression and blah blah blah,
you have a higher risk of those UTIs getting up
into your kidneys and causing a kidney infection.

Speaker 1 (01:08:18):
Okay, does that is that risk consistent throughout pregnancy?

Speaker 5 (01:08:22):
I don't have an answer to that question. Okay, it's
a good question.

Speaker 4 (01:08:26):
And it's not like it's major, like that's not like,
oh my god. It's just like you're a little bit
higher some of the things that some of the things
that can happen.

Speaker 5 (01:08:33):
So that was a lot.

Speaker 4 (01:08:34):
Someone take a big breath, just kidding. You can't take
a deep breath during pregnancy.

Speaker 1 (01:08:40):
Did you have that written now?

Speaker 6 (01:08:41):
I did.

Speaker 5 (01:08:41):
It was a joke, I wrote.

Speaker 1 (01:08:44):
I love when your jokes are written out.

Speaker 6 (01:08:45):
Thank you.

Speaker 1 (01:08:46):
Still felt natural.

Speaker 5 (01:08:48):
Thank you.

Speaker 4 (01:08:48):
It was my segue into the respiratory system.

Speaker 1 (01:08:50):
It's a good seg thank you.

Speaker 4 (01:08:52):
So the changes that happen in your respiratory system, they
actually start really early in pregnancy. I think we think
about the changes later in pregnancy when you have a
large volume that's compressing things, and we'll get there. But
the hormonal changes actually cause an increase in ventilation called
hyperventilation of pregnancy, and that starts really early. So your

(01:09:12):
respiratory rate actually increases hormonally.

Speaker 1 (01:09:15):
Okay, hormonally what hormone progesterone mostly progesterone. How does that work?

Speaker 4 (01:09:25):
We're not going to go deep into mechanism here, Aaron,
because I got too many other bodies make talk about it.
I don't know why not have any answer to that
in what I wrote so far, but I got plenty
of papers that you can read about.

Speaker 5 (01:09:36):
Because it does it.

Speaker 1 (01:09:37):
Yeah, I'm just yeah, amazing, It's so cool.

Speaker 4 (01:09:40):
And then, as I have alluded too many times now,
as pregnancy progresses and this uterus increases in size significantly,
it displaces every single other organ in your abdomen. It
moves from being a pelvic organ to an abdominal organ,
and in doing so, it elevates your diaphragm, which is
that muscle between your chest and your belly, and your

(01:10:01):
diaphragm is what allows for your lungs to expand. It
has to move down for you to take a deep
breath in. During pregnancy, this gets shoved about four centimeters upward,
so your lungs cannot expand as fully as they could previously.
That's what also causes that displacement of the heart, which
gets pushed up and a little bit to the left.

(01:10:23):
And now some of this is compensated for this displacement
is compensated for by the same hormones like progesterone and
also other ones like relaxing in things that cause ligamentous laxity.

Speaker 1 (01:10:33):
There's a hormone called relaxing, relax and just relaxing. I
want to know who named that.

Speaker 5 (01:10:41):
I have no idea.

Speaker 1 (01:10:42):
That's a main question. Relaxin.

Speaker 4 (01:10:44):
Yeah, so it's what allows all of your ligaments to
expand and relax so that you can like.

Speaker 5 (01:10:49):
Fit a baby through your pelvist.

Speaker 4 (01:10:51):
And then also so that the bottom part of your
rib cage can flail out and actually expand in diameter
this way, like front to back, about five to seven centimeters.

Speaker 5 (01:11:01):
You get change here.

Speaker 4 (01:11:03):
Wow, just the bottom part of your ribs all thanks
to relaxing, well, relax in, progesterone, all of these hormones.

Speaker 1 (01:11:08):
Not to throw a spotlight weight relaxes.

Speaker 4 (01:11:11):
Spotlight it, I know, give it some cred. But with
all of these changes combined, by the end of pregnancy,
your total lung capacity decreases by about five percent, which
isn't huge. However, because of increased demand, both because the
fetus has increased demand, right you have to share with

(01:11:32):
the fetus, and because your own basal metabolic rate during
pregnancy increases by about fifteen percent. Your total oxygen consumption
and need goes up by twenty to thirty percent.

Speaker 1 (01:11:46):
Okay, so you've got first of all, you're breathing more
because progesterone is telling me to breathe more.

Speaker 5 (01:11:52):
Yep, that's how it goes.

Speaker 1 (01:11:54):
We're somehow dig deeper into that. You've got less room
for your lungs to expand, and you.

Speaker 5 (01:12:01):
Need to breathe more, need more oxygen.

Speaker 1 (01:12:03):
And so you're you're like just like panting.

Speaker 5 (01:12:06):
You feel a little bit shorter breath, short breath. Yes, yeah,
you're not panting, but you feel.

Speaker 1 (01:12:13):
Okay, And then and then there's like is that and
then also the metal ball. Yeah, okay, there's a lot
of a lot of things.

Speaker 4 (01:12:20):
There's a lot of reasons to feel a little bit
shorter breath, especially towards the end of pregnancy. Now you
also have, because of everything going on in your abdomen, right,
you also have just a lot of pressure inside of
your abdomen. And what this can do, especially if somebody
ends up lying down flat on their back, is it
can put pressure on the blood vessel that sends blood

(01:12:42):
back to your heart. Called the inferior vena cava, and
that because it's a vein, it has floppy walls, so
it can actually become compressed later in pregnancy by the
weight of the fetus and the uterus and everything else
in there, and that can potentially be problematic, mostly for
the fetus, because it can kind of reduce the blood

(01:13:03):
flow back to the heart, thus reducing your cardiac output.
And then you can have this drop in blood pressure
that affects the profusion to the fetus. Okay, so that's
why a lot of times late in pregnancy people are
told like, don't lay flat on your back. Yeah, that's
the reason why. Okay, yeah, we have so many more
body systems. Okay, ready, blood in general, going back a

(01:13:24):
little bit, I guess blood clotting factors completely changed during pregnancy.
Nearly all of our clotting factors increase except for our
platelet count. And we think this is helpful in terms
of preventing postpartum hemorrhage. Oh, but it also means that
people are at higher risk of a thrombotic event of
a blood clot forming when it shouldn't.

Speaker 1 (01:13:44):
But I thought that our blood was less viscous.

Speaker 5 (01:13:46):
Oh my gosh, it is, but our clotting factors are higher.

Speaker 1 (01:13:50):
Okay, so we're just sort of compensating for that in
different viscosity and then it's like the clotting factors, I mean, really,
we're getting to the same end result. Yeah, yeah, yeah,
more clots, potential.

Speaker 4 (01:14:02):
Potential for more clots. And the mechanism there, don't ask
me exactly, is probably related to estrogen because some reason,
if you're on estrogen birth control, you're at higher risk,
which but not as high risk as when you're pregnant.

Speaker 1 (01:14:12):
How have we not talked about that?

Speaker 5 (01:14:13):
Okay we did, I thought during our birth control upsote.
Oh yeah we did, Yeah, we did.

Speaker 4 (01:14:18):
Okay, But all of this I've talked about so far,
which was a lot and I've already skipped over what
is a lot of people's first indication symptom wise that
they might be pregnant, and that is the changes to
our GI track.

Speaker 5 (01:14:30):
Yeah.

Speaker 4 (01:14:31):
So from the very beginning of pregnancy, hormones again like
progesterone and others are causing smooth muscle relaxation. That's how
we get dilation of our blood vessels. That's why we
get the stasis in our bladder. All these things, and
this results in a decrease in tone of our esophageal sphincter,
which goes from our esophagus into our stomach, and that

(01:14:52):
can mean that you get an increase of things like
acid reflux. And we think that it's also related to nausea. Right,
you have just like slow down of your GI tract
and opening of your esophagus and going in so it
just makes you feel more nauseous.

Speaker 1 (01:15:06):
Why does why does the slow down happen.

Speaker 5 (01:15:09):
Because of progesterone?

Speaker 8 (01:15:10):
Yeah?

Speaker 5 (01:15:10):
But why?

Speaker 1 (01:15:11):
Yeah?

Speaker 4 (01:15:12):
Is it just a consequence of the fact that like
progesterone is causing this overall relaxation probably, like it.

Speaker 5 (01:15:17):
Does it have a purpose? I don't know, Okay?

Speaker 1 (01:15:19):
And then why does that lead to nausea? Like what
is nausea?

Speaker 6 (01:15:23):
Oh?

Speaker 1 (01:15:23):
My, sorry, I.

Speaker 5 (01:15:25):
Can't believe the questions you're asking me right now. Well,
I'm sorry, it's like what is itch?

Speaker 1 (01:15:30):
Oh my gosh, I still want to know what it is?
It's yeah, I mean, I mean I know what nausea.

Speaker 5 (01:15:37):
Is, right, you know what it feels like?

Speaker 9 (01:15:39):
Right?

Speaker 4 (01:15:39):
Like why does having I mean you can think about
it too, as like your food is not able to
move through as quickly so it's going to be sitting
there for longer. You have things that are in you're
supposed to be staying in your stomach coming up into
your esophagus more readily.

Speaker 8 (01:15:53):
OK.

Speaker 4 (01:15:53):
Like, I don't I don't know a better answer than that,
And there's probably a better answer out there, like a
GI doc is like rolling right now. Sorry, No, I'm sorry, No,
don't be sorry. But but yes, so this this happens.
And what's interesting is that mild nausea and vomiting early

(01:16:14):
in pregnancy is actually associated with a lower risk of
miscarriage or early pregnancy loss in the first trimester.

Speaker 1 (01:16:20):
Yes, I have heard that.

Speaker 4 (01:16:22):
Yes, and so we think that it's that is a
big part of the reason that we think it's very
progesterone mediated, right, is that when you have adequate levels
of progesterone, then your pregnancy is able to continue. And
so if you have lesser then you might have less nausea.
But then it also might mean.

Speaker 5 (01:16:39):
You know what I'm saying, Yeah, I do know what
you're saying, but it's not it's not cut and dry.

Speaker 4 (01:16:42):
It's just like a slight association. Okay, But as you
can also hear in several of our first hand accounts.
Sometimes this nausea and vomiting can become very severe, and
that's called hyperremesis gravidarum. We do not fully understand the
cause of hyperemesis. We think that it's probably in part
these changes to the gastrointestinal tract and the mobility of

(01:17:03):
our gaster intestinal tract, but also like some contribution of
is it maybe other hormones, like independent of their effect
on the GI tract, there's probably some degree of genetic susceptibility.

Speaker 5 (01:17:14):
We don't know.

Speaker 4 (01:17:15):
In short, Okay, yeah, we don't fully understand that one
at all. Yeah, but this slowdown of the GI tract
can also, especially later in pregnancy, end up affecting the
liver and the gall bladder, and that is what can
result in intrahepatic colistasis of pregnancy or colas stasis.

Speaker 1 (01:17:32):
Yes, I want to know more about this. This is
I had only heard.

Speaker 4 (01:17:35):
Yeah, yeah, yeah, so this is it's more rare than
some of the other complications like maybe anemia or something
like that. It's estimated at zero point two to two
percent of pregnancies, depending on which studies you're looking at.
But colostasis is when we see a build up of
bile acids because bio acids are supposed to be they're
made in the liver and then they have to be

(01:17:56):
transported through a duct into the gall bladder. They're stored,
and then from the gall bladder they have to be
squeezed out and then squirted into our small intestine. Okay,
And so we see a build up of these bile
acid because they're not being squirted out and excreted by
the gall bladder.

Speaker 1 (01:18:11):
They're stuck in the gall blader. Their stup latter is
the source of so much issue.

Speaker 4 (01:18:15):
Like right, and so they're also then just they're not
they're building up in general. So it's like the liver,
the gallbladder, the whole situation. They're not going down the
track like they're supposed to.

Speaker 1 (01:18:25):
Okay, and so the salts are stuck in the liver,
stuck in the gall it's just sort of like a
again the slow down, slow down. It's a slow down, yeah,
traffic jam in the gall blade.

Speaker 5 (01:18:34):
Traffic jam.

Speaker 4 (01:18:35):
And so then this bile acid accumulation will then be
essentially like transported out of just the liver gall bladder
situation and can potentially end up in our bloodstream. So
then we see an increase in bio salts in our bloodstream.
The symptoms of that end up being really really severe itching,
and it's usually like whole body itching. Don't ask me
why it causes itching?

Speaker 1 (01:18:55):
What is itch? How does it get in the bloodstream.

Speaker 4 (01:18:57):
Because it's not able to be transported out, so then
there's just too much of it, and it's just like, ah, okay, okay,
because your liver like has so much blood supply, and
so if it's just backed up into your liver.

Speaker 1 (01:19:09):
Then it's gonna be it's gonna go okay.

Speaker 4 (01:19:13):
And so yeah, and the that does not pose a
problem to the pregnant person, but those bile salts can
pass through the placenta and be toxic to the fetus
because these are cytotoxic compounds, right, That's why they're usually
stored in our gall bladder where they're not causing problems. Usually, Okay,

(01:19:35):
I've gone through a lot of physiologic changes so far.

Speaker 5 (01:19:38):
Try to think of other don't ask me more questions.
I'm gonna keep going.

Speaker 4 (01:19:42):
I don't think of other body parts, like or what
other body system. They're not the ones you would think
of necessarily. Yeah, brain is interesting your brain definitely changes
during pregnancy, and there are like fetal cells that make
it all the way into your brain.

Speaker 5 (01:19:54):
Yeah, but we don't I don't have data on like
what are the changes.

Speaker 1 (01:19:57):
We have no idea but the feel cell.

Speaker 4 (01:20:00):
Okay, But here's what I'm going to do is now
focus more on the two other major complications that we
see and the body systems that they're involved in. So diabetes,
h Okay, this is our endocrine system. And we already
know that our endocrine system, which is our hormone system.
You defined it last episode. I could be at some point.

Speaker 1 (01:20:24):
Oh yeah, it was last episode. Because we've talked about hCG.

Speaker 4 (01:20:28):
So our entire hormonal milieu is changed during pregnancy, and
people end up susceptible to diabetes during pregnancy in large
part because of a hormone that the placenta is secreting
that's called human placental lactogen. There's other stuff that it's
involved as well. But this is what I'm going to
focus on, because what this does is it makes our

(01:20:48):
pregnant bodies less sensitive to insulin. We have an increased
insulin resistance. Okay, why do we need an increased insulence resistance?
If we remember back to our diabetes episode, insulince job.
What it does in our body is when we have
high glucose and are like we eat something, right, and
we have high glucose in our bloodstream, Insulin is secreted
and it tells the glucose like, get away from here,

(01:21:11):
pack yourself away so that we can store you and
use you later. Okay, So insulin puts glucose into our cells.
But a fetus needs glucose and they get it from
our blood stream.

Speaker 8 (01:21:23):
Got it.

Speaker 4 (01:21:23):
So by making our insulin less effective, you can have
more glucose to be available for the developing fetus. But
if this process goes too far, like if are pancreas,
because we're going to have this insulin resistance, right, so
our cells are going to recognize, hey, glucose is too high,
we need to make more insulin. If you're pincreas can't
keep up with that increased demand, then you end up

(01:21:45):
with gestational diabetes where we see too much glucose in
our bloodstream. Levels get too high, and that has a
couple of big consequences. One is it can cause increased
growth of the fetus. Right, because the fed is just
like getting a glucose pipeline. Yeah, yeah, okay, and that
is called macrostomia. So it ends up being large. Babies

(01:22:07):
are large for gestational age babies, and that can make
delivery very risky.

Speaker 5 (01:22:11):
Yes, okay.

Speaker 4 (01:22:12):
But the second complication that I don't think people talk
about as much is that while our glucose that's in
our bloodstream passes through the placenta and into the fetus,
our insulin does not. So if our glucose levels get
really really high, fetus inside of us has to make
more and more insulin because their body is also like, whoa,

(01:22:35):
this is a lot of glucose. So they're having an
increase amount of fetal insulin that they're making. And then
after they're born, that sugar syrup bloodstream pipeline is cut off,
and now they can get severely hypoglycemic because of how
much insulin they've made in their bodies.

Speaker 1 (01:22:51):
And so then what does that look like?

Speaker 4 (01:22:53):
That can end up with seizures or coma or death.
And that is like to imediately immediately following birth right
or when yeah, exactly in the neonate in the new
moral they can have really severe hypogacemia. And so that's
why Babies that are born when the mom has had
just national diabetes have to be monitored really closely, especially
in the first like twenty four to forty eight hours.

Speaker 1 (01:23:12):
Okay, so interesting. Can I ask some questions or you
can try yeah, okay, okay, okay, okay. When typically do
we see uh, gestational diabetes appear?

Speaker 4 (01:23:25):
Okay, we usually test for it around weeks twenty four
to twenty eight Okay. Doesn't mean it can't happen before
that or after that, but that's usually in most places,
that's the timeline that we test for it.

Speaker 1 (01:23:34):
Okay. My second question is then what do you do
about it?

Speaker 3 (01:23:37):
Yeah?

Speaker 4 (01:23:37):
Great question. Okay, do you have more that you want
to keep going?

Speaker 8 (01:23:40):
Yeah?

Speaker 1 (01:23:41):
No, no, but you answer that okay, yeah.

Speaker 3 (01:23:43):
Uh.

Speaker 4 (01:23:43):
There's a few different things a lot of times that
can be managed with just dietary changes alone, and so
figuring out like what do you what are you eating
that's maybe causing really big glucose spikes and can you
just modify your diet to be able to have not
have that and then you're good. Otherwise it's usually insulin,
so we manage it with it.

Speaker 1 (01:24:01):
My third question, and you may maybe I should just
let you finish talking about the other complication. What are
the differences between first pregnancies and subsequent pregnancies and the
path this big, big picture question, you know, because I
would I would imagine that like, Okay, first pregnancies, your

(01:24:21):
body is like responding and doing all these things that
it's doing for the first has never done it right,
and the second time, it's like are those pathways carved out?
How different are the hormone levels? How likely are same
complications to occur between one pregnancy and subsequent pregnancies.

Speaker 4 (01:24:36):
That's interesting. So we'll talk definitely more about that with preclamcya,
which is what I'm going to do next. But I
don't know when it comes to just stational diabetes. Certainly,
if you've had just stational diabetes in one pregnancy, you
are at higher risk for having it in another pregnancy.
Just stational diabetes is also associated with an increased risk
of type two diabetes later in life. So it's thought
to be kind of like a marker. There's a lot

(01:24:57):
of things that happen in pregnancy that are thought to
kind of be markers, and we I don't know are
they like causal or are they just like a kind
of a snapshot in time where we're like, oh, maybe
you are at higher risk for these complications later in life,
but it's not like because you had it during pregnancy.

Speaker 5 (01:25:12):
Does that make sense?

Speaker 8 (01:25:12):
Yes?

Speaker 4 (01:25:14):
But yeah, I don't. I don't know data on like
what are the rates first pregnancy, second third. It also
is going to vary with age as well too, so yeah,
I don't know. That's an interesting question though. When it
comes to diabetes.

Speaker 5 (01:25:25):
Yeah, I don't know.

Speaker 4 (01:25:26):
Overall though, the rate the estimates of like how many
pregnancies are complicated by diabetes are like all over the map.

Speaker 5 (01:25:33):
From like one to thirty percent depending on your studies.

Speaker 1 (01:25:35):
So it's like what's food, what's the threshold? Like how
do you? How do you?

Speaker 5 (01:25:39):
How do you diagnose?

Speaker 1 (01:25:39):
How do you diagnosed?

Speaker 4 (01:25:40):
I really wanted to bring in a glue coola for you,
but I couldn't get my hands on ones.

Speaker 5 (01:25:45):
I'm sorry.

Speaker 4 (01:25:46):
And it does differ different countries and different guidelines are
a little bit different in terms of what how you
how exactly you diagnose it. But most of the time
it's by doing a glucose tolerance test, and so you
give somebody a fixed volume of glucose seventy five grams whatever,
and then you test their blood at intervals either one hour,
two hours, three hours, or multiple times, and then see

(01:26:07):
what their numbers are. Got it, what their glucose level
is Okay, And there's different cutoffs, and that part's pouring.
So let's move on, shall we.

Speaker 1 (01:26:14):
Yeah, I want to pre aclampsia. Ye, big one, So
that is it is the biggest.

Speaker 4 (01:26:20):
It is a doozy and it can be for sure
probably the most severe complication of pregnancy.

Speaker 5 (01:26:24):
That might not be true, but it's a big one.

Speaker 1 (01:26:26):
It's a big one.

Speaker 4 (01:26:27):
So this is really truly not just it doesn't fit
as neatly in a single organ system, because it is,
like you mentioned Aaron, the result of a kind of
dysfunctional relationship really between the placenta and our own cardiovascular system,
and it can result in a whole spectrum of disorders
that we call hypertensive disorders of pregnancy. So it's not

(01:26:50):
just preaclamsia. It also includes gestational hypertension. So just high
blood pressure, okay, preeclampsia and aclampsia, and then also help
which is hemolysis, elevated liver enzymes, and low platelets. But
often we think about and focus on preeclampsia, because that
is a kind of point at which if this kicks in,

(01:27:13):
if it's officially preeclampsia, then that's when the risks to
both fetus and mom become pretty significant. Okay, preeclampsia overall
is estimated to complicate between four and five percent of
all pregnancies worldwide.

Speaker 1 (01:27:27):
That's such a high rate.

Speaker 4 (01:27:28):
It's pretty high, and it's estimated and estimason This really
did vary in several papers that I read, but most
reliably the papers that I read said it's estimated to
result in seventy thousand maternal deaths every year. Seventy thousand
maternal deaths every year, and five hundred thousand steel births

(01:27:50):
or neonatal deaths, oh my gosh, which is just like
heartbreakingly massive numbers. On top of that, for every maternal
death that's really to preeclampsia, it's estimated that fifty to
one hundred women are having significant morbidity as a result
of it. So it's like affecting a huge number of people. Yeah,

(01:28:11):
and I'm sorry that that started off like so heavy,
but preclamsy can.

Speaker 5 (01:28:14):
Get really scary.

Speaker 4 (01:28:15):
Yeah, absolutely so, in terms of like what is when
I say preclamcy, what does that mean? It's defined as hypertension,
so elevated blood pressures and at least one of a
few other features symptoms that we see. One big one
is protein in the urine, because that's a sign that
your kidney is being affected, okay, or sometimes other signs,

(01:28:37):
other lab values that we see that tell us that
your kidney is having kidney dysfunction, and that's like it's
not filtering exactly exactly, or liver dysfunction, all right, and
all of those we do like laboratory values to see
what those numbers are. Or sometimes it's diagnosed by neurologic complications,
which can be severe persistent headaches, visual changes, stroke or

(01:29:01):
abnormal reflexes. Or sometimes it's hematologic complications, especially platelet abnormalities.

Speaker 1 (01:29:08):
Okay, So there are a multitude of ways to dultitude.

Speaker 4 (01:29:11):
Of criteria that you kind of like check the boxes,
and if you're meeting these then it's called preeclampsia rather
than just hypertension.

Speaker 1 (01:29:20):
Interesting, Yeah, So that it would have to be like
these neurological changes in addition to high blood pressure exactly,
and you would also have to have protein in the
urine or exact other liver enzyme elevation, okay.

Speaker 4 (01:29:33):
And what it can cause is a number of different things.
From the fetal perspective, it can cause fetal growth restriction
because of abnormal blood flow into the placenta. But when preeclampsia,
especially if it goes untreated or unchecked, it can result
in a number of really severe complications, including a clampsia,

(01:29:54):
which is preeclampsia but with seizures. So that's the line
at which it becomes a clampsy Yeah, right, than preeclampsia
down to down to nabby, I know, I think of
that too. And then it also can sometimes cause stroke,
especially a hemorrhagic stroke, which would be a very severe
complication of preeclampsia. Sometimes it's not the nervous system, but

(01:30:15):
it's a different organ that gets mainly affected. So it
can cause severe liver damage and that often results in
that HELP syndrome. Okay, because it's causing damage to the liver.

Speaker 1 (01:30:25):
Yeah, So help is A is A is A. It's
on the spectrum what so Okay, So what is that spectrum?
I know there's there's high hypertension.

Speaker 4 (01:30:35):
Gestational hypertension, preeclampsia, eclampsia, help, okay, Yeah, that's like the
main spectrum, okay, But then within preeclampsia, we can also
see these other companies and they're not discrete events necessarily,
like it's not like help or this sure, right, okay, yeah,
And pre eclampsia also, it doesn't discriminate. It can cause

(01:30:58):
severe complications to your kidneys and end up causing renal failure.
It can cause flash pulmonary edema, meaning fluid onto the lungs,
largely from just such high blood pressures, because that's something
we see with severely elevated blood pressures outside of pregnancy
as well. And then, like I said, for the fetus,
it can cause placental abruption as well, which is where

(01:31:19):
the placenta detaches spontaneously before the baby has been delivered,
and that can be potentially catastrophic and then also premature
delivery or still birth. And we don't fully understand the
mechanisms of preoclampsia, but you talked a lot Aarin about
what we know about the placenta and this relationship between

(01:31:40):
abnormal or whether it's inadequate, like not deep enough or
too deep placentation and what we think is that that
process results in these anti angiogenic factors that float around
in our maternal bloodstream and end up causing damage to
our blood vessels, and that causes us to have this

(01:32:03):
increase in blood pressure and that is what ultimately leads
to preeclampsia. So it's like inflammation and these like anti
angiogenics like not making enough blood vessels, not getting enough
remodeling in the uterus, and this whole like kind of
perfect storm.

Speaker 1 (01:32:19):
Almost signaling like, hey, there's not enough going on here,
Send more, send more.

Speaker 5 (01:32:24):
Exactly exactly.

Speaker 4 (01:32:26):
And there are there is of course, a lot of
interest in understanding like are there biomarkers. Are there things
that we can identify, like in your blood to say
either you definitely have preoclampsia or you are at higher
risk of developing preeclampsia. And in several countries they actually
do use a few different blood tests that test for
a few different specific things. And I think I forgot

(01:32:48):
to write down their names, but they're like PIF blah
blah blah, some biomarkers exactly biomarkers. So far, as of
twenty twenty four, we don't use those yet in the
United States. So what we mostly look at in terms
of trying to identify who is at risk for developing
preeclampsia is what we know from the epidemiological data, and

(01:33:10):
we know a lot about what the risk factors are
that make someone higher risk for developing preeclampsia. We know
that one of the biggest ones is having a previous
pregnancy with preoclamsia.

Speaker 7 (01:33:20):
Right.

Speaker 4 (01:33:21):
The other huge one is having a first pregnancy. So
you asked about the difference between like first pregnancies and
subsequent pregnancies. First pregnancies are generally higher risk for preeclampsia
compared to second, third, fourth pregnancies unless you had preoclamsia
in your first one, right, And then you're at higher
risk during the other ones as well too, And we
don't fully understand that, but we think that it's related

(01:33:43):
again to this immune tolerance thing, where your body has
never seen these cells from this fetus floating around and
you develop this immune response to it. Whereas if you've
had a pregnancy before and your immune system tolerated it,
you are at lower risk of having an abnormal reaction
to them that in the future pregnancies. Yeah, if they're
with the same paternal DNA that so.

Speaker 1 (01:34:05):
That I find fascinating and I didn't get into this,
but there is a lot about paternal DNA and like
pre like exposure to paternal DNA before ye pregnancy.

Speaker 4 (01:34:17):
Yeah, so like IVF pregnancies, especially those with donor sperm,
are also a little bit higher risk than non IVF
pregnancies or IVF without donor sperm. So it's really that's
part of what lends support to this idea that there's
like an immune tolerance spectrum kind of a thing.

Speaker 1 (01:34:31):
Well, and it also makes sense then where why subsequent
pregnancies where the first pregnancy there's preeclampsy, I would have
pre eclamsy because it's almost sensitized exactly. Well, I've seen
this before, right.

Speaker 4 (01:34:44):
And I know what to do, Yeah, right, exactly. There's
a lot of other risk factors though, having chronic hypertension
prior to pregnancy, maternal age, so increasing age increases our
risk why we do not know. And then a lot
of other like complications that might affect the functioning of
your organs prior to pregnancy, like kidney disease, things like lupus,

(01:35:07):
which can affect blood clotting factors and things like that,
having a family history of preeclampsia. And then this part's
really important, especially in the United States, race is a
risk factor for preeclampsia. Specifically, Black people who are pregnant
are at significantly higher risk of pre eclamsia compared to

(01:35:28):
white people who are pregnant. But that is not a
biologic difference, and that this is specified in the ACOG guidelines.
This is due to systemic racism. Because we also see
that low income, regardless of race, which causes increase in
life stressors, is also associated with an increased risk of preeclampsia.

(01:35:48):
And so these are the kinds of differences that are
really important to understand because by recognizing who is at risk,
we can can we hopefully prevent preeclampsia.

Speaker 1 (01:35:58):
How would prevent preeclampsia?

Speaker 4 (01:36:01):
So glad that you asked, Darren right now, The only
thing that we have to help prevent preeclampsia is low
dose aspirin, of all things. Okay, So taking aspirin, which
we did a whole episode on and you might remember,
is an anti inflammatory agent that also irreversibly inhibits platelets
from aggregating, so it stops your platelets from forming clots.

(01:36:24):
And we think that these, like microthrombotic events are involved
in the pathogenesis of preeclampsia and so by irreversibly inhibiting
this platelet aggregation, we've shown through a lot of epidemiological
studies that's what we think the mechanism is. But we
know that starting low dose aspirin early in pregnancy, usually
first or early second trimester, and continuing it until term

(01:36:46):
can significantly reduce someone's risk of developing pre eclampsia, not
make it zero. And the risks are different for whether
it's term preeclamsia, pre term preclamsia, or postpartum preeclamsia.

Speaker 1 (01:36:59):
So what are those I don't have like they sound.

Speaker 5 (01:37:03):
Like they are.

Speaker 4 (01:37:04):
They sound like it's like when in whin in pregnancy,
does it develop? Yeah, most of the time, this is
something that does not develop, or at least we don't
see it. Can't recognize it clinically until after twenty weeks
of pregnancy, okay, but it can potentially develop any time.
We might just not like you might just not see
the signs it might be. That's part of why people
are looking for biomarkers. Can we find it. Can we
find evidence of this super early on? Yeah, but usually

(01:37:27):
it's after twenty weeks, the earlier that you start to
see pre aclamsia. Usually the worst the outcomes are, which
makes sense, yeah, because you're just going to have a
bigger effect on the fetus and you're gonna have a
longer time that you're having potentially complications to the mother
as well, and postpartum and postpartum we really do not understand.
But you can develop preclamsia for the first time postpartum,

(01:37:48):
even if you did not have high blood pressure during pregnancy.
We have no idea, no, And it is thought that
like term, because some people also don't develop preclamsy until
like right at the end, right they're after term, you're
after thirty seven weeks, and you now all of a
sudden have high blood pressure and then potentially preeclamsia. And
we think that maybe those two entities are slightly different

(01:38:11):
and less related to inadequate placentation early on, but maybe
some other mechanism, but we don't know what that mechanism
is yet, Like.

Speaker 1 (01:38:19):
Is that the same, Is it related to any bits
of the placenta remaining or like getting stuck.

Speaker 4 (01:38:25):
To Sometimes, yes, it can be from the placenta not
fully detaching or something like that, but not always. So
it's not as like clear cut as that.

Speaker 1 (01:38:32):
Right, Okay, there's still something that's sending that the signal
of there's not enough foxygen exactly.

Speaker 4 (01:38:38):
Okay, yeah, but we don't know exactly how it works.
How is it different or is it not different?

Speaker 5 (01:38:43):
And that kind of a thing.

Speaker 4 (01:38:45):
In terms of other ways that we have to reduce
the risk of preaclamsia, there's some evidence that maybe calcium
supplementation might help, but it's not as clear cut as aspirin.
And then in terms of if someone has preclamsia, how
can we prevent it from getting severe or how do
we cure it? Magnesium sulfate is given to prevent seizures,

(01:39:05):
so specifically to prevent eclampsia. We don't know the mechanism
or why it works, but it does. But the only
cure for preclamsia is delivery of the fetus and the placenta.
But that is not only something that you have to
balance getting to a gestational age where the fetus can
survive and hopefully thrive and also ensuring the health of

(01:39:28):
the pregnant person. And of course that's not always the
case because postpart in preclamsia does still exist. So it's
a little bit complicated and we don't fully understand it.

Speaker 1 (01:39:40):
Do you have a breakdown for the percentages of you.

Speaker 4 (01:39:43):
And I really tried to find that, but I don't.
I don't have a I don't have a good breakdown
of that. Yeah, so that's preclamsia. And really, like the
overall physiology of pregnancy, what about breasts. I wasn't gonna
talk about breast until two episodes. They do start to
change early on in pregnancy. Yeah, you actually start to

(01:40:03):
make colostrum in like the second trimester, which is the
first like stuff that you secrete. Right after that, the
newborn usually eats for the first couple of days before
your actual milk comes in.

Speaker 1 (01:40:14):
Food aversions, food cravings.

Speaker 5 (01:40:16):
I don't know.

Speaker 4 (01:40:17):
Okay, there's a lot of talk about like the evolutionary
significance of nausea and vomiting and food cravings.

Speaker 1 (01:40:23):
And is it so that we speaks at the time
that the fetus is most vulnerable to toxins crossing the
placental Yeah, but I don't know. I mean, there seems
to be some basis to that, like Darwinian medicine or whatever, but.

Speaker 5 (01:40:36):
I don't know more about it than that.

Speaker 4 (01:40:38):
But what I think is so interesting and part of
the reason that I am so astounded by and fascinated
by the physiology of pregnancy is that despite all of
these changes to literally every organ system in our body,
and despite all of the possible complications, some of which

(01:40:59):
might be minor and not result in severe harm, and
some of which can be very severe, despite all of that,
the majority of pregnancies progress all the way to term
and delivery without major complication, which is just astounding.

Speaker 7 (01:41:19):
It is.

Speaker 1 (01:41:19):
It is mind blowing that our bodies can change so dramatically.
I have a question about that, Okay, permanent changes, What
are there? And then how like what you can tell
whether someone has been pregnant before anatom like looking at
a lot.

Speaker 5 (01:41:39):
Of times, I mean not all the time, h not
all the time?

Speaker 1 (01:41:41):
Yeah, what what are those things that give that that
like signal that We'll.

Speaker 4 (01:41:45):
Talk probably more about that in the fourth episode when
we talk about postpartum stuff. Okay, So yeah, I don't
have like an easy answer to that question. Okay, but yeah,
I mean things change, like in terms of cervix changes
and things like that that you can like maybe see
on physical exam. There are there is evidence that like
fetal cells remain in our tissues for like potentially the

(01:42:06):
rest of our lives, which is crazy to think about it.

Speaker 1 (01:42:08):
I mean again, it kind of is that relationship with
cancer where it's like yeah, yeah, yeah, interesting, it's really
really interesting.

Speaker 5 (01:42:15):
But yeah, that's pregnancy erin.

Speaker 1 (01:42:21):
In a short short and a half years that I've
took to explain all of that, we went from a
deep time. We've really crossed hundreds of millions of years.

Speaker 5 (01:42:30):
Deep time all the way until delivery, which is deep
time delivery.

Speaker 1 (01:42:35):
Yeah.

Speaker 5 (01:42:37):
So so if you'd like to learn more sources, boy, howdy,
boy howdy, Okay, I have some sources here. Oh I bet.

Speaker 1 (01:42:46):
There are two books that I read. One is called
The Evolution of the Human Placenta, which is what it
sounds like by Michael Power and Jay Schulkin. And then
there's Life's Vital Link The Astonishing Role of the Placenta
by Young Look. Then, uh, those are the books. I
think they were pretty good overviews of what's going on.
It is an overwhelming amount of information. If you want

(01:43:07):
to learn more about retroviruses, there are a few papers
that I have posted. One is by Chung from twenty
thirteen called Retroviruses facilitate the rapid evolution of the mammalian placenta.

Speaker 9 (01:43:16):
Love it.

Speaker 1 (01:43:17):
There are some other ones too about retroviruses that are good.
Then there's shits at All from twenty nineteen, Evolution of
placental invasion and cancer metastasis are causally linked.

Speaker 5 (01:43:28):
Ooh yeah, interesting, interesting, bold statement.

Speaker 1 (01:43:31):
Bold statement. Then from twenty thirteen by Crosley Placental invasion,
preeclampsia risk, and adaptive molecular evolution at the origin of
the Great apes evidence from genome wide analyzes because humans
are not the only species to get preeclampsia, which we
thought for the longest time that we were.

Speaker 9 (01:43:49):
But no.

Speaker 1 (01:43:49):
I think there was a gorilla at the Houston Zoo
last year the year before something that had preeclampsia or
baby I know, she.

Speaker 5 (01:43:57):
Okay, I think, so, okay good.

Speaker 4 (01:44:00):
I have a number of sources for this, some of
which focus more on just the basic physiology of pregnancy.
One that I liked that was easy to read was
called Physiology of Pregnancy from Anesthesion Intensive Care Medicine from
twenty nineteen. I had a few others that were more
focused on the cardiovascular physiology of pregnancy too that were great.
A review paper on just stational diabetes called Justational Diabetes

(01:44:21):
melodis really creative title from Nature Reviews Disease Primers twenty nineteen,
and another from Nature Reviews Disease Primers on pre acclamsia
called preaclamsia not really creative titling. I mean, I feel
like it's pretty easy to understand what the is, what
the papers are that know what you're getting.

Speaker 1 (01:44:36):
It's real puns puns.

Speaker 4 (01:44:38):
In this and then there was a bunch more so
listen check out our website this podcast will Kill You
dot com under the episode's tab, where you can find
the list of all of the sources that we used
from this episode in every single one of our episodes.

Speaker 1 (01:44:48):
Single one. A huge thank you again to everyone who
sent in their first hand account and shared them with us.
We really can't thank you enough. Thank you, thank you,
thank you, thank you.

Speaker 5 (01:44:58):
We'll try though.

Speaker 4 (01:45:00):
Thank you again to everybody here at Exactly Right Studios
for having us. We're super excited about it. Thank you Tom,
thank you Leana, thank you Jessica, thank you Brent, thank you,
Craig everyone.

Speaker 1 (01:45:10):
Thank you everyone. There's so many other people's do so
much fun it has.

Speaker 9 (01:45:13):
Yeah.

Speaker 1 (01:45:14):
Thank you to Bloodmobile for providing the music for this
episode and all of our episodes.

Speaker 4 (01:45:18):
And thank you to all of you for listening and watching.
And we hope that you enjoyed this episode and that
you're ready for two more to more.

Speaker 1 (01:45:26):
I know we still have so much to cover its
wow yea. And thank you to our patrons. You really
you mean a lot to us. We really appreciate you.

Speaker 5 (01:45:34):
Yeah, thank you.

Speaker 8 (01:45:35):
Yeah.

Speaker 5 (01:45:35):
Well, until next time, wash your handsalthy animals, U.

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Erin Welsh

Erin Allmann Updyke

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.css-14f5ked{margin:0;word-break:break-word;display:-webkit-box;-webkit-box-orient:vertical;box-orient:vertical;-webkit-line-clamp:2;overflow:hidden;}Ep 169 Pregnancy: Act 2