Unfortunately, not all pregnancies result in a perfectly healthy baby. According to the Centers for Disease Control and Prevention:
- About 8% of babies born annually in the United States are classified as low birth weight, which puts them at risk of a variety of developmental problems.
- Preeclampsia—a dangerous pregnancy complication characterized by a spike in blood pressure and protein in the urine—affects millions of women every year.
- One in every 100 to 200 U.S. pregnancies ends in a stillbirth, defined as the death of a fetus after 209 weeks of pregnancy.
There is currently no effective method for predicting which pregnant women and their babies are most at risk for these outcomes in late pregnancy. Researchers in the Program in Perinatal Research and Obstetrics within the Division of Intramural Research investigated whether testing levels of certain chemical signals in the mothers’ blood during the first half of the third trimester could help predict risk of these outcomes. Previous research suggested that these chemical signals, which are involved in blood vessel growth, could be part of the processes that cause some of these adverse outcomes.
The researchers found that the relative levels of several of these signals in the blood predicted the risk of preeclampsia and stillbirth, but did not predict the risk of the baby’s being born at a low birth weight.
Looking into these predictions in more detail, the researchers found that the third trimester measurements of these blood chemicals predicted late-pregnancy preeclampsia risk better than did first- and second-trimester measurements. They also found that measuring the blood chemical signals seemed to be most effective at predicting the risk of stillbirth due to problems with the placenta, rather than stillbirth due to other causes.
Currently, there are no effective interventions to reverse the late-pregnancy risks identified by these biomarkers. However, these results open new avenues for understanding how preeclampsia and stillbirth happen, and they point to potential targets for new methods to prevent them (PMID: 23333542).