Pregnancy at age 40 and beyond is an independent risk factor for intrauterine fetal demise or stillbirth, according to an abstract presented by Yale School of Medicine researchers at the Society for Maternal-Fetal Medicine Conference February 10 in San Francisco.

The researchers also found that fetal testing at 38 weeks gestation has the greatest impact at reducing stillbirth rates in older women.

Pregnant patients of advanced maternal age (AMA) are at increased risk for a multitude of pregnancy complications, including gestational diabetes mellitus, preeclampsia, placenta previa and intrauterine growth restriction. All of these conditions have been associated with a higher rate of stillbirth.

To determine if AMA was an independent risk factor for stillbirth, and when fetal testing would be most beneficial for reducing stillbirth rates, the authors conducted a cross-sectional study using the United States CDC perinatal mortality database. The database is made up of 11,061,599 singleton deliveries between 1995 and 1997. The women in the study were between 15 to 44 years of age who were at least 37 weeks pregnant.

"Our results support routine antenatal testing in those women who are over age 40, beginning at 38 weeks gestation," said first author Mert Ozan Bahtiyar, M.D., professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine. "This will help identify women who are most at risk for stillbirth.