Is the “Aging” of the Placenta a Problem?
One common myth surrounding the end of pregnancy is the idea that the placenta “ages” and stops working as well. But the “aging” of the placenta isn’t a problem; it’s normal, and it’s more like maturing than getting old.
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One of the things about pregnancy that fascinates me is the placenta.
The placenta is the only temporary organ. During pregnancy, a woman grows not only a baby but a full new organ to support that baby. After the baby is born, the placenta is born and its time has come to an end.
The way the placenta functions and nourishes the baby is truly miraculous. It is a beautiful element in a divinely designed process.
But my point today isn’t just to talk about how amazing placentas are. My goal is to address the common belief that placentas somehow stop working properly after a certain point in pregnancy.
While “placental insufficiency” (the woefully unhelpful medical term for it) can happen, it is rarer than many women are led to believe.
So let’s talk about it.
The Placenta’s Purpose
Real quick, I want to make sure we all know the purpose of the placenta. The placenta, like I said, is the organ that grows inside a mother’s uterus, along with her baby. It is connected to the baby by the umbilical cord.
The placenta and umbilical cord deliver nutrients and oxygen from the mother’s blood to the baby’s blood and growing body.
The placenta is the literal lifeline of the baby.
By the time a baby is ready to be born, the placenta will be roughly 1 inch thick and 8 inches in diameter. By about 40 weeks, blood flow from mom to placenta and baby is about 700 mL (or 3 cups) every minute!
(So if you’re in the third trimester and feeling tired, know your body is doing a LOT of work.)
What’s the Deal With “Placental Insufficiency”?
The term you’ll hear doctors use when talking about placentas they think aren’t working properly is “placental insufficiency.” I thoroughly despise that term.
No woman who chooses to give birth to a baby is “insufficient” but that is exactly how she is going to feel if she’s told she has “placental insufficiency.”
You’ll likely hear the statistic that 10–15% of pregnancies are affected by placental insufficiency. However, the research indicates that that may be how often it is diagnosed but not how often there is a real problem.
The truth is that placentas are rarely, if ever, truly “insufficient.” Placentas have a wide range of normal.
Beyond that, the most common time for a woman’s placenta to be deemed insufficient is as she nears or passes her due date. She is told that her placenta is aging and that it isn’t functioning as well as it was a few weeks ago.
But is that really true?
Well…usually? No.
Let’s talk about why.
Why Not to Worry About an Aging Placenta
To understand the truth about how placentas change over time and how that affects the baby, I’ve broken things down into 5 reasons not to worry about the “aging” of the placenta.
1 – Change doesn’t equal deterioration.
First and foremost, we need to clear something up: there’s a difference between change over time and deterioration. This point is made clear in an influential paper on the changes that a placenta experiences over time.
Dr. Harold Fox, in that paper, explains the development of a placenta over 5 stages, from the beginning of pregnancy through the end. He also refutes several common claims about the “aging” of the placenta.
By his definition, “maturation” means “increased functional efficiency” while “aging” indicates
“decreased functional efficiency.”
And in his paper he illustrates this point: Placentas mature. They don’t age.
No evidence exists that shows that a placenta ages in a negative way. And, quite the opposite, many things suggest that the placenta has an incredible ability to adapt to existing circumstances and give the baby what it needs, even after 40 weeks.
2 – The placenta likely isn’t the problem.
Sometimes complications happen. Occasionally, a placenta won’t work as it is supposed to and thus put the baby at risk. But that is rare. And you will usually know that is the case long before you reach 40 weeks.
Plus, in cases where complications do happen at the end of pregnancy, they are very likely not due to problems with the placenta.
In other words, placental problems are usually a symptom, not a cause.
For example, the placenta of a woman who develops preeclampsia may not function as well. But the decreased function of the placenta at the end of this woman’s pregnancy isn’t because of its age; it’s because of the preeclampsia.
(And preeclampsia is often caused by insufficient nutrition during pregnancy.)
As Dr. Fox, in that same study as above, states, “It seems…quite clear that any ill effects which may befall the [baby] in prolonged [pregnancies] can not be attributed to placental insufficiency or [aging].”
3 – Babies (and placentas) don’t care about due dates.
The next reason not to worry about the “aging” of the placenta is that the whole idea of a “due date” is made up. It’s a theory, an average, a guess based on math.
But a baby’s due date isn’t determined by math; it’s determined by the baby. Each baby—and placenta—is on their own schedule.
Because of genetics, health habits of mom, and lots of other factors, some babies are ready to be born at 39 weeks. Some at 43. And many somewhere in between. And the placenta, except in rare cases, is fully prepared to nourish that baby as long as is needed.
My first daughter was “due” on April 1. That was 40 weeks. She was born after 17 hours of unmedicated labor on April 10.
By the medical world’s standard, she was 9 days late. But I truly believe she was right on time.
So don’t worry about how far past your “due date” you are. Your baby will come exactly when they are ready and your placenta will adapt and mature as long as your baby needs.
4 – Your placenta isn’t like anyone else’s.
The next thing to consider when told that your placenta is “aging” is the fact that every woman, every baby, and every birth is unique. A blanket statement about placentas in general (for example, “all placentas lose function after 40 weeks”) probably doesn’t mean a thing about yours.
If a doctor tells you that your placenta is going to stop working now that you’re past 40 weeks (or 42, or any point), it would be wise to ask what it is about your placenta or your baby that seems to indicate that.
Did a recent ultrasound show signs of decreased blood flow? Has the placenta begun to detach from the wall of the uterus? Is your baby moving less than they used to?
While I’m not suggesting you phrase the question exactly the way I wrote it, if your doctor doesn’t have an individualized reason for recommending you get induced because of an “aging” placenta, you may want to get a second opinion.
5 – Nothing is risk-free.
Finally, no option is 100% without risk. Choosing to stay pregnant despite being past your due date carries risk. But so does getting induced.
This really is the foundation of so much of the work I do. There’s a reason that things like induction and c-sections are part of the world of birth. But too many women are told an induction (or c-section, etc.) will be best without being given all the information.
Truly informed consent can only happen if a woman is told about all of her options and the risks and benefits of each.
Sometimes an induction because of placental problems will be the best course of action because it is more dangerous for mom or baby if the pregnancy continues. And sometimes the opposite will be true.
But that decision can only really be made by a mother, and only when that mother has been told about the risks of doing the thing that is recommended and the risks of not doing it.
And that simply isn’t happening for most women.
To summarize, induction carries these risks:
- Accidental prematurity
- Possibility of a failed induction
- The cascade of interventions
- Discomfort, pain, and infection
- Use of synthetic hormone Pitocin and its associated risks
To read more about the risks (and some benefits, to be fair!), check out Understanding Induction: Pros and Cons of Inducing Labor.
Conclusion: Your Placenta is Sufficient
To sum up, many women are diagnosed with “placental insufficiency,” which is based on the belief that placentas get old and don’t function like they should after a certain length of time.
Though placental problems do happen and can cause problems for the baby, they are more rare than common. In fact, many researchers have concluded that “placental insufficiency” is simply a false diagnosis.
If you are confronted with the issue of a prolonged pregnancy and the “aging” of the placenta, remember these 7 points:
- Change doesn’t equal deterioration.
- The placenta likely isn’t the problem.
- Babies (and placentas) don’t care about due dates.
- Your placenta isn’t like anyone else’s.
- Nothing is risk-free.
Most of all, remember, you—and your placenta—were created for this.
Until next time,
Allison
P.S. If you want to get deeper into this subject, you’ll find a wonderful technical debunking of this myth HERE.
READ MORE:
Amniotic Fluid Levels: Separating Fact from Fear
Understanding Ultrasound Safety: Both Sides of the Story
