A new study reveals that pregnancy risk factors like preeclampsia, having a low-birth weight baby, or stillbirth can now be identified in the first trimester.
Your placenta is crucial to keeping your pregnancy healthy—it transfers nutrients and blood to your baby, helping her develop and grow. Poorly functioning placentas can lead to pregnancy complications like preeclampsia (dangerously high blood pressure), fetal growth restriction (small babies) and even stillbirth. Previously, doctors weren't able to determine if a pregnant woman's placenta was working well until the effects could actually be seen, and by then it was difficult to treat. Researchers are making progress in catching these conditions earlier—one report recently identified some markers for preeclampsia. Now, a new study in The American Journal of Pathology has discovered more about why some placentas don't develop normally early on, leading to problems later.
First trimester screenings
Using a special ultrasound called a uterine artery Doppler, researchers at St. George's Hospital, University of London measured the blood flow to the uterus and placenta of almost ten thousand women in the first trimester. They charted the results on the Resistance Index (RI), which measures the difference in blood flow with each contraction and relaxation of the mother's heartbeat. "High resistance means that the placental bed the mothers blood is flowing into is more restricted, a tight pipe rather than a wide open channel, which leads to resistance to flow in the feeding vessels," study author Karin Leslie, MD, an OBGYN, tells Fit Pregnancy. After looking at the outcomes of the pregnancies, the study found that those women with the highest resistance scores had almost five times the risk of developing a later complication like preeclampsia or fetal growth restriction compared to women with a normal RI—a 24 percent chance instead of 4.9 percent. "We think that failings in the complicated relationship between the mothers cells and fetal placental cells lead to a failure of the mothers blood vessels adapting," Leslie says.
The study also found possible causes why placentas in women with high RIs don't function as well, including differences in gene expression, the health of placental cells, and the regulation of proteins and antioxidant enzymes. "We found that higher levels of cell death in the placenta and a lack of vital growth factors early on in pregnancy may be linked to problems in later pregnancy," Leslie says.
New treatments ahead
So what does this mean for pregnant women? Understanding the reasons why some placentas don't work as well starting in the first trimester can help doctors figure out how better to treat them. "A lot of work has been done on this and lots of things tried," Leslie says. So far, treatment for women at risk of developing placental complications has been low-dose aspirin, which helps blood flow. "There are new studies going on looking at statins [drugs that lower cholesterol] to prevent preeclampsia and sildenafil [Viagra] to improve blood flow to very tiny babies, but these are all in very early day stages," Leslie says. In terms of what you can do to lessen your chances of having these complications, "having a normal body mass index and avoiding significant weight gain between babies reduces risk," Leslie says.
As conditions like preeclampsia progress, there's not much that can be done, which is why identifying earlier risk factors is crucial. "Once the disease starts there is at present little we can do other than deliver," Leslie says. More effective treatments based on info about the placenta gathered earlier could help reduce pregnancy complications later. "The placenta is crucial for nine months as a life support—it does everything for the baby—yet we think very little of it," she says. "It's an amazing and fascinating organ."