Newborn Death Risk Halved When Pregnancy Lasts 39 Weeks

If you’re pregnant and thinking about scheduling your labor and delivery a little earlier than week 40, new research might make you think twice. Babies have long been considered ready for delivery any time after 37 weeks of pregnancy. But researchers are learning that gestation weeks 38, 39 and 40 can make a big difference – cutting the risk of newborn death significantly.

A study in the June issue of Obstetrics and Gynecology looked at the difference in mortality rate between infants born in 2006 at 37, 38, 39 and 40 weeks’ gestation. The number of deaths was highest at 37 weeks (just under four per 1,000 live births), declining each week and reaching a low of almost two per 1,000 births at 40 weeks.

The study, conducted by the March of Dimes, the National Institutes of Health and the U.S. Food and Drug Administration, highlights the need to make sure that elective deliveries – those agreed upon by the expectant parents and doctor – aren’t scheduled before 39 or 40 weeks of pregnancy unless the baby needs to be delivered early for medical reasons.

These results echo a January 2009 study – also using 2006 data – in the New England Journal of Medicine, which found that babies delivered by elective Caesarean section before 39 weeks were more than twice as likely to have serious breathing problems, bacterial infections, low blood sugar, or to spend time in intensive care than those delivered at 39 weeks’ gestation.

The 2009 study of more than 28,000 women also found that babies delivered at 37 weeks were more than four times as likely to have these problems. All of the women in the study had had prior elective C-sections as well. About 31 percent of babies were born via C-section in 2006, and, in the study, nearly 36 percent of elective repeat C-sections were performed before 39 weeks.

–    Christina Elston


Posted May 2011