Becca Bressler

So in the world of Harvey's analogy here, PP13 is blowing up the grocery store. The placenta produces it. It goes off to some other part of the uterus that the placenta isn't trying to invade.

So in the world of Harvey's analogy here, PP13 is blowing up the grocery store. The placenta produces it. It goes off to some other part of the uterus that the placenta isn't trying to invade.

So in the world of Harvey's analogy here, PP13 is blowing up the grocery store. The placenta produces it. It goes off to some other part of the uterus that the placenta isn't trying to invade.

And while the whole police force is over there dealing with the PP-13, the placenta's digging claws bust through.

And while the whole police force is over there dealing with the PP-13, the placenta's digging claws bust through.

And while the whole police force is over there dealing with the PP-13, the placenta's digging claws bust through.

And this can also go wrong in the other direction.

And this can also go wrong in the other direction.

And this can also go wrong in the other direction.

But if neither side wins the war, then after nine months, give or take a few weeks... You have a baby. And poof is exactly what it feels like.

But if neither side wins the war, then after nine months, give or take a few weeks... You have a baby. And poof is exactly what it feels like.

But if neither side wins the war, then after nine months, give or take a few weeks... You have a baby. And poof is exactly what it feels like.

Yeah. And then Harvey told us how the placenta, this little alien invader and all its thirsty veins and tendrils and hooks, how it leaves the body.

Yeah. And then Harvey told us how the placenta, this little alien invader and all its thirsty veins and tendrils and hooks, how it leaves the body.

Yeah. And then Harvey told us how the placenta, this little alien invader and all its thirsty veins and tendrils and hooks, how it leaves the body.

And they do, like immediately. There's this river of blood fountaining into the placenta that just shuts off.

And they do, like immediately. There's this river of blood fountaining into the placenta that just shuts off.

And they do, like immediately. There's this river of blood fountaining into the placenta that just shuts off.

Yeah, in some sense, I think of it as like the OG parent for the baby. It's one mission is to help that embryo grow into a healthy fetus and deliver a baby. And it's developed this sort of like incredible way of somehow making sure all of its needs are met in such a selfless sort of way that I've started seeing it as the first parent.

Yeah, in some sense, I think of it as like the OG parent for the baby. It's one mission is to help that embryo grow into a healthy fetus and deliver a baby. And it's developed this sort of like incredible way of somehow making sure all of its needs are met in such a selfless sort of way that I've started seeing it as the first parent.

Yeah, in some sense, I think of it as like the OG parent for the baby. It's one mission is to help that embryo grow into a healthy fetus and deliver a baby. And it's developed this sort of like incredible way of somehow making sure all of its needs are met in such a selfless sort of way that I've started seeing it as the first parent.

I mean, I guess it goes in the garbage most of the time. I feel really sad that I can't meet mine. I think once you know all that it's done for you, I just wish I could meet it.

I mean, I guess it goes in the garbage most of the time. I feel really sad that I can't meet mine. I think once you know all that it's done for you, I just wish I could meet it.

I mean, I guess it goes in the garbage most of the time. I feel really sad that I can't meet mine. I think once you know all that it's done for you, I just wish I could meet it.

Yeah, and hold it.

Yeah, and hold it.

Yeah, and hold it.

Put it in my closet. I don't know.

Put it in my closet. I don't know.

Put it in my closet. I don't know.

Tina was living in Michigan.

Tina was living in Michigan.

Tina was living in Michigan.

How did that make you feel when you heard that?

How did that make you feel when you heard that?

How did that make you feel when you heard that?

We got to send that family this podcast. I'm sure we can't know who they are, hip-hop.

We got to send that family this podcast. I'm sure we can't know who they are, hip-hop.

We got to send that family this podcast. I'm sure we can't know who they are, hip-hop.

Let me turn it down.

Let me turn it down.

Let me turn it down.

This is Harvey.

This is Harvey.

This is Harvey.

He studies the placenta.

He studies the placenta.

He studies the placenta.

Where he has a cabinet of placentas.

Where he has a cabinet of placentas.

Where he has a cabinet of placentas.

Which we visited. We'll come back to that.

Which we visited. We'll come back to that.

Which we visited. We'll come back to that.

But before we do...

But before we do...

But before we do...

So about 40 years ago, Harvey's just gotten out of medical school.

So about 40 years ago, Harvey's just gotten out of medical school.

So about 40 years ago, Harvey's just gotten out of medical school.

Studying ovaries.

Studying ovaries.

Studying ovaries.

And these other scientists in the lab ended up with this thing called a gradient, where the different kinds of cells in the placenta were sort of separated out. They can look at them independently.

And these other scientists in the lab ended up with this thing called a gradient, where the different kinds of cells in the placenta were sort of separated out. They can look at them independently.

And these other scientists in the lab ended up with this thing called a gradient, where the different kinds of cells in the placenta were sort of separated out. They can look at them independently.

He saw these cells, sort of a bubbling cauldron of cells.

He saw these cells, sort of a bubbling cauldron of cells.

He saw these cells, sort of a bubbling cauldron of cells.

Later, he'd make movies of them.

Later, he'd make movies of them.

Later, he'd make movies of them.

They were growing very aggressively in a way that surprised him.

They were growing very aggressively in a way that surprised him.

They were growing very aggressively in a way that surprised him.

And that's the story we're going to tell you.

And that's the story we're going to tell you.

And that's the story we're going to tell you.

Okay, so Harvey says the first thing you have to understand is that that tiny embryo with its little baby placenta cells wrapped around it like a blanket, it is not welcome in the mother's body.

Okay, so Harvey says the first thing you have to understand is that that tiny embryo with its little baby placenta cells wrapped around it like a blanket, it is not welcome in the mother's body.

Okay, so Harvey says the first thing you have to understand is that that tiny embryo with its little baby placenta cells wrapped around it like a blanket, it is not welcome in the mother's body.

You know, the pregnancy is a little bit genetically the mom, but also a little bit the dad.

You know, the pregnancy is a little bit genetically the mom, but also a little bit the dad.

You know, the pregnancy is a little bit genetically the mom, but also a little bit the dad.

Which, for the mother's body, is not normal.

Which, for the mother's body, is not normal.

Which, for the mother's body, is not normal.

Melissa Wilson, geneticist at Arizona State. We need to get rid of not-self.

Melissa Wilson, geneticist at Arizona State. We need to get rid of not-self.

Melissa Wilson, geneticist at Arizona State. We need to get rid of not-self.

And so if an embryo just waltzes into a uterus one day without a little placenta blanket around it, the mother's body would gather up a squad of white blood cells, send them out to find it, shred it apart, and kill it.

And so if an embryo just waltzes into a uterus one day without a little placenta blanket around it, the mother's body would gather up a squad of white blood cells, send them out to find it, shred it apart, and kill it.

And so if an embryo just waltzes into a uterus one day without a little placenta blanket around it, the mother's body would gather up a squad of white blood cells, send them out to find it, shred it apart, and kill it.

So the placenta is in the uterus looking around for food. And it does this thing, something kind of tricky, something that when we heard about it actually feels like it's skipping ahead nine months. Harvey says it produces this hormone, HCG, happens to be the hormone that activates pregnancy tests.

So the placenta is in the uterus looking around for food. And it does this thing, something kind of tricky, something that when we heard about it actually feels like it's skipping ahead nine months. Harvey says it produces this hormone, HCG, happens to be the hormone that activates pregnancy tests.

So the placenta is in the uterus looking around for food. And it does this thing, something kind of tricky, something that when we heard about it actually feels like it's skipping ahead nine months. Harvey says it produces this hormone, HCG, happens to be the hormone that activates pregnancy tests.

Yeah. But this milk is like a snack for the placenta. What it really needs is blood. So at this point, about two weeks into the pregnancy, the placenta goes on the offensive. By now, it's actually latched onto the side of the uterus.

Yeah. But this milk is like a snack for the placenta. What it really needs is blood. So at this point, about two weeks into the pregnancy, the placenta goes on the offensive. By now, it's actually latched onto the side of the uterus.

Yeah. But this milk is like a snack for the placenta. What it really needs is blood. So at this point, about two weeks into the pregnancy, the placenta goes on the offensive. By now, it's actually latched onto the side of the uterus.

And what you start to see is this push and pull where the placenta keeps digging, digging, digging.

And what you start to see is this push and pull where the placenta keeps digging, digging, digging.

And what you start to see is this push and pull where the placenta keeps digging, digging, digging.

You're listening to Radiolab.

You're listening to Radiolab.

You're listening to Radiolab.

is just getting started. Week five goes by, then week six, week seven, the embryos growing eyes, ears, bones.

is just getting started. Week five goes by, then week six, week seven, the embryos growing eyes, ears, bones.

is just getting started. Week five goes by, then week six, week seven, the embryos growing eyes, ears, bones.

Meanwhile, the placenta is digging, digging, digging, trying to get to the blood to get this thing more nutrients. But the placenta just can't break through.

Meanwhile, the placenta is digging, digging, digging, trying to get to the blood to get this thing more nutrients. But the placenta just can't break through.

Meanwhile, the placenta is digging, digging, digging, trying to get to the blood to get this thing more nutrients. But the placenta just can't break through.

Specifically, one trick called PP13. It's a protein that Harvey says creates a diversion.

Specifically, one trick called PP13. It's a protein that Harvey says creates a diversion.

Specifically, one trick called PP13. It's a protein that Harvey says creates a diversion.