Editor’s note: Child loss is a painful topic but we know it must be discussed. Readers who have experience with stillbirth or another form of child loss may find this article difficult to read. But it will also fill them with hope as they learn about a life-saving technology.
The first trimester of pregnancy is filled with lots of different emotions. For many parents, this often includes anxiety as the statistic “1 in 4 pregnancies result in miscarriage” weighs on their minds and hearts. After the first trimester, many families feel a sense of relief and give themselves permission to announce the pregnancy, decorate the nursery, and set up a crib.
However, in about 1 in 160 pregnancies, the tragedy of child loss occurs after 20 weeks gestation. Whereas child loss before 20 weeks is called miscarriage, after 20 weeks gestation it is called stillbirth. The Centers for Disease Prevention and Control (CDC) reports around 21,000 stillbirths every year. For so many parents, the shock of this loss is absolute. Questions abound. How is this happening? What went wrong? Is there anything that could have been done? And… could this happen to us again?
In many cases, these questions are never answered. Approximately 1 in 3 stillbirths have no known cause. They are simply treated as mysterious, unexplainable events. But the unknowns stand in the way of parents finding a sense of closure as they grieve. Our lack of knowledge and understanding around stillbirth is a major roadblock to our ability to ensure it doesn’t happen to anyone else.
This may be about to change. Researchers at Yale University have come up with a deceptively simple stillbirth prevention tool—three extra measurements on standard prenatal ultrasounds to identify the number one cause of stillbirth.
What’s the connection between stillbirth and placenta problems?
In order to understand how the stillbirth prevention tool works, we first have to learn the connection between stillbirth and placenta problems.
While historically 1 in 3 stillbirths were said to have no known cause, researchers at Yale University identified the cause of stillbirth in nearly 99% of studied cases (and 92% of all pregnancy loss, including miscarriage)! The researchers examined 1,256 pathology slides from pregnancies that ended in loss [1]. Researchers found that the most common causes of stillbirth were small placenta (34%), dysmorphic chorionic villi (31%) and umbilical cord accidents (15%). According to Johns Hopkins Medicine, chorionic villi are “tiny projections of placental tissue that look like fingers and contain the same genetic material as the fetus.” Abnormalities seen in chorionic villus cells often indicate that the fetus has a genetic abnormality, as tested for by chorionic villus sampling. Previously, stillbirths caused by small placenta or chorionic villi problems (a total of 65% of cases from the study) would have been considered “unexplained.”
The Yale study was unable to determine why a placenta would not grow properly or would develop normally to a point and then stop growing or grow too slowly. Certainly more clarity on why that happens is important. The stillbirth prevention tool doesn’t clarify why poor placental growth is happening, but, crucially, it can accurately identify when it does.
“Measure the Placenta” to prevent stillbirths
Dr. Harvey Kliman, the senior author and lead pathologist for the Yale study, found that the best practice to prevent stillbirths is to “Measure the placenta!” Luckily, Dr. Kliman also provided the tool for the job as he and his father, Merwin Kliman, developed a technique to measure Estimated Placental Volume (EPV) during pregnancy. This technique simply adds an additional component to a typical ultrasound exam rather than creating more tests for the mother to undergo.
During a routine ultrasound exam, EPV is determined by taking three measurements of the placenta that are then inputted into an equation. The Klimans even created an app for healthcare providers to do the math!
Isn’t the placenta always measured during ultrasounds?
While placenta location is usually noted in ultrasound exams (and this matters in case the mom has placenta previa or another condition that requires a Cesarean section), placental size is not something physicians typically monitor. The Measure the Placenta website encourages women to ask their providers to take this measurement each time they have an ultrasound. The goal is to flag pregnancies that may need additional monitoring.
Is measuring EPV enough to prevent stillbirth?
If a placenta measures small, your provider will likely consider additional factors such as the size of the placenta relative to the size of the baby, signs of fetal compromise, cord blood flow, signs of placenta deterioration, and gestational age before making the decision to induce. But having an EPV measurement that indicates an abnormally small placenta will help put your medical team on high alert and make kick counting all the more important in the third trimester to watch for signs of fetal distress.
Why you should ask your doctor to Measure the Placenta
The best tools in medicine are relatively cheap, easy to use, and effective. EPV seems to check all of these boxes while providing doctors a way to monitor for the number one cause of unexplained stillbirth: an abnormally small placenta. While the ability to measure EPV has been around for over a decade, most pregnant women still haven’t heard of it. As this measurement is not yet widely used, it may take some advocacy to have EPV checked.
In one of the personal stories shared on the Measure the Placenta app, Hope Carr shares how her request for an EPV measurement was denied due to her pregnancy seeming normal, despite her fears of stillbirth due to previous pregnancy loss. Hope’s fears turned out to be well-founded as, following her early induction due to high blood pressure, her baby’s placenta measured at only the 1.4th percentile. Her baby measured in the 10th percentile. Dr. Kliman suspected that the small placenta contributed to the high blood pressure Hope experienced, which luckily prompted her medical team to schedule an induction before her baby became more distressed.
In other stories on the website however, the only warning sign that the baby was struggling to receive proper nutrition and oxygen through an abnormally small placenta was a decrease in fetal movement. Asking for an EPV measurement can help to identify these high-risk cases beforehand and give you support if you find yourself asking for an induction due to lack of fetal movement.
Lives are at stake and measuring the placenta can make a real difference
The heartrending stories shared on Measure the Placenta and other stillbirth awareness websites like PUSH for Empowered Pregnancy underscore the utter urgency of incorporating estimated placental volume measurements into routine prenatal ultrasounds. Mom of loss Jennica wrote on the Measure the Placenta website, “I don’t blame any of our care providers for Hugo’s death, because I know they did the best they could with the knowledge they had. But I do blame the system for not taking action sooner to make Estimated Placental Volume measurements standard care for all pregnant people. This should not happen. Period.” Long term, measuring estimated placental volume (just remember, “Measure the placenta!”) could lead to thousands more happy and healthy birth-days each year.
References:
[1] Thompson, B.B., Holzer, P.H. & Kliman, H.J. Placental Pathology Findings in Unexplained Pregnancy Losses. Reprod. Sci. 31, 488–504 (2024). https://doi.org/10.1007/s43032-023-01344-3Additional Reading:
Resources for emotional healing after miscarriage and other forms of child loss
