NEW YORK — Move over, Mother Nature. First-time mothers at low risk of complications were less likely to need a caesarean delivery if labor was induced at 39 weeks instead of waiting for it to start on its own, a large study found. Their babies fared better, too.

The results overturn the longtime view that inducing labor raises the risk for a C-section and prompted two leading OB-GYN doctor groups to say it’s now reasonable to offer women like those in the study that option.

Only certain pregnant women qualify, and the study did not track how inducing labor affected breastfeeding or other mother-baby issues later. Some groups such as Lamaze International still advocate letting nature take its course.

‘‘Many women don’t want all of the medical care that goes with induction’’ such as an IV and fetal monitoring, said Lisa Kane Low, past president of the American College of Nurse-Midwives and associate dean of the University of Michigan School of Nursing.

About 40 percent of US women giving birth are first-time mothers.

Previous studies suggesting that inducing labor raises the risk for a C-section were observational and compared different types of women giving birth under different types of circumstances. This was the first very big experiment to time labor induction for 39 weeks — when a pregnancy is considered full term.

associated press