Researchers previously thought that inducing labor, even at 39 weeks, would increase the rate of cesarean sections, but they found the number of C-section deliveries actually lowered.

Woman Holding Newborn In Hospital After Labor
Credit: Natalia Deriabina/Shutterstock

A recent study in New England Journal of Medicine found that when doctors induce labor in a first-time mother at 39 weeks, it can reduce the chance that the mom-to-be will deliver via a cesarean section, compared to her waiting to deliver naturally at full term.

The study, which followed about 6,100 healthy, first-time mothers-to-be at 41 hospitals, also found that inducing labor at 39 weeks could lower a mother's risk for pregnancy-related hypertension and postpartum infections.

In the past, medical professionals have generally been told to avoid inductions at this time in first-time mothers. "The reason for this recommendation was that there was a belief that induction increases cesarean delivery and may harm the baby. However, this belief was not based on strong evidence," said George R. Saade, M.D., an obstetrics and gynecology professor at the University of Texas Medical Branch in Galveston, Texas, who was involved in the study.

According to the study, delivery via C-section is generally considered safe for mother and baby, yet since it is a major surgery, it poses increased complication risks and longer recovery time compared to a vaginal delivery.

Delivery Outcomes

To conduct this study, researchers separated the mothers-to-be into two groups. One group elected to have an induction at 39 weeks, which is considered full term. Women in the other group were monitored to see if spontaneous labor began at and after 39 weeks but would receive the appropriate intervention if needed.

Those who chose the induction, on average, delivered about a week earlier than women who waited for labor to begin naturally. C-sections were less likely after an elective induction—18.6 percent of women who were induced had a C-section, while 22.2 percent of the watched waiters had the operation.

The study found that inducing labor at 39 weeks is at least as safe as spontaneous labor, since a composite score measuring health indicators in newborns, including death, seizures, hemorrhage, and trauma, was not significantly different between the two groups.

The researchers said that inducing could eliminate the need for a C-section in one out of every 28 deliveries.

When to Induce?

Though evidence shows an induction at 39 weeks does not increase the likelihood of a C-section, women shouldn't feel like they should be induced at 39 weeks, Saade cautioned. "What this study says is that there should not be any universal ban on elective induction at or after 39 weeks," he added.

Saade noted that women in the study had very accurate dating, so doctors could tell exactly when they hit 39 weeks. "Sometimes, the dates are not very accurate and in these cases, the induction should not be done unless there is a medical indication," he added.

"These results open the door for pregnant women and their health care providers to talk about what the woman wants to do," Michael Varner, M.D., vice chair for research in Obstetrics and Gynecology at U of U Health, told Science Daily.