The study showed that women in the first trimester of pregnancy with the lowest levels of a certain protein were 40 times more likely to have a stillbirth caused by a dysfunctional placenta than women with higher levels.
Researchers say low levels of the protein, known as pregnancy-associated plasma protein A (PAPP-A), in the first 10 weeks of pregnancy may be a strong indicator of stillbirth risk for women without other risk factors.
Stillbirth affects about one in 200 pregnancies. Although several factors appear to increase the risk of stillbirth, such as older age of the mother, smoking, and obesity, researchers say most of these factors are only weakly associated with stillbirth risk.
Stillbirth Risk May Be Determined During First Trimester
In this study, which appears in the Nov. 10 issue of The Journal of the American Medical Association, researchers looked at whether the risk of stillbirth might be determined during the first trimester by using a blood test that measures for pregnancy-related proteins.
Researchers examined the records of nearly 8,000 women who gave birth in Scotland from 1998 to 2000. All of the women had blood samples taken during the 10 weeks after conception and were entered into national registries of live births and stillbirths. Researchers divided the women into five groups based on their level of PAPP-A.
The study showed that eight stillbirths occurred among the 400 women with the lowest level of PAPP-A compared with 17 stillbirths among the remaining 7,534 women.
When researchers analyzed the data by cause of stillbirth, they found low PAPP-A was strongly associated with stillbirth due to placenta dysfunction, which is an unexplained stillbirth caused by growth restriction or a rupture of blood vessels of the placenta.
Women in this lowest fifth had a 40 times greater risk of stillbirth due to these causes of placenta dysfunction.
But having a low PAPP-A was not associated with other causes of stillbirth. It was also not related to the mother's age, ethnicity, weight, or other demographic factors.
Researchers say the findings suggest that stillbirth may be the end result of impaired placental function during the first trimester, as measured by the level of this protein.