Yale Obstetrics and Gynecology scientist Mert Ozan Bahtiyar, M.D., presented the findings today at the annual meeting of the Society for Maternal Fetal Medicine, held February 7-12 in Reno, Nevada.
"Caesarean sections have been associated with some pregnancy complications, but when a physician consults a woman with prior caesarean sections about her next pregnancy, stillbirth should not be one of the concerns," said Bahtiyar.
Fetal death or stillbirth is an underappreciated problem, according to Bahtiyar, who said that stillbirths account for more perinatal deaths than do complications of prematurity or sudden infant death syndrome. Some risk factors for stillbirth include history of a prior stillbirth, a mother over the age of 35, smoking, substance abuse, and underlying medical conditions such as diabetes, hypertension or preeclampsia. A previous study by researchers in England found that prior caesarean delivery was also a factor in increased risk of stillbirth.
Bahtiyar and his team decided to confirm the previous study using U.S. data from the Centers for Disease Control and Prevention's combined birth and death certificates from 1995 to 1997. They used a statistical analysis method called Cochran-Mantel-Haenszel to determine the odds of fetal death after prior caesarean section.
"We used a much larger data set of 250,000 patients than the British study, which used 16,000 patients," said Bahtiyar. "We were not expecting different results, but we found that prior caesarean section did not increase the risk of future stillbirth."
Co-authors included Joshua Copel, M.D., Charles J. Lockwood, M.D., and Errol R. Norwitz, M.D., of Yale; and Julian Robinson, M.D., Lambert Lumey, M.D., and Patricia Zybert, M.D., of Columbia.