Elective induction at 39 weeks also linked to lower risk of maternal high blood pressure disorders.

Healthy first-time mothers whose labor was induced in the 39th week of pregnancy were less likely to deliver by cesarean section, compared to those who waited for labor to begin naturally, according to a study funded by the National Institutes of Health. Researchers also found that infants born to women induced at 39 weeks were no more likely to experience stillbirth, newborn death or other severe complications, compared to infants born to uninduced women. The study results are published in the New England Journal of Medicine.

“Our analysis suggests that elective induction at 39 weeks is associated with a lower rate of cesarean delivery and does not increase the risk of major complications for newborns.” Said the authors.

The study enrolled more than 6,000 pregnant women at 41 hospitals participating in the NICHD-supported Maternal-Fetal Medicine Units Network. Roughly half of the women were assigned at random to have their labor induced in the 39th week of pregnancy; the remaining women received expectant management.

The researchers compared births between the two groups in terms of a primary outcome, a composite measure that included death of the baby during or after birth; the newborn’s need for respiratory support; seizure, infection, birth trauma (injury) or hemorrhage; and other birth complications.

The primary outcome occurred in 4.3 percent of the induced labor group and 5.4 percent of the expectant management group, a difference that was not statistically significant. However, the proportion of cesarean delivery was significantly lower for the induced group (18.6 percent), compared to the other group (22.2 percent). Similarly, the rate of blood pressure disorders of pregnancy was significantly lower in women who were induced (9.1 percent), compared to the other group (14.1 percent).

The researchers estimate that one cesarean delivery could be avoided for every 28 low-risk, first-time mothers undergoing elective induction at 39 weeks.