A new study of nearly 6 million births has found that "the risk of deaths to newborns delivered by voluntary Caesarean section is much higher than previously believed," the New York Times reports. The study, which will be published in this month's issue of Birth: Issues in Prenatal Care, is particularly important because, according to its authors, it is the first to examine the risk of cesarean delivery among low-risk mothers "who have no known medical reason for the operation."
While mortality in cesarean deliveries has "consistently been about 1 = times that of vaginal births," the Times reports, it was thought that the difference was because of the higher-risk profiles of the mothers -- women for whom the operation was medically necessary. However, the study shows that even for low-risk mothers the neonatal mortality rate for cesarean delivery is 1.77 deaths per 1,000 live births, while the rate for vaginal delivery is 0.62 deaths per 1,000 live births.
Researchers still aren't entirely sure why C-section delivery appears to carry a significantly higher risk than vaginal birth, even for low-risk mothers. According to the article, even when the researchers eliminated intrauterine hypoxia -- aka lack of oxygen, which is one of the leading causes of death during C-sections -- neonatal mortality remained twice that of vaginal births.
But even without definitive answers, Michael H. Malloy, a coauthor of the article and a professor of pediatrics at the University of Texas Medical Branch at Galveston, told the Times he hopes that the study will "promote greater discussion within the obstetrical community about the pros and cons of offering C-sections for convenience and promote more research into understanding why this increased risk persists."