In what could be viewed as a practice changing result, a study has found that compared with expectant management, elective induction of labor at 39 weeks in low-risk nulliparous women reduced the chances of cesarean births. Also, 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 the expectant management group.
The multicenter study enrolled more than 6,000 pregnant women at 41 hospitals participating in the NICHD-supported Maternal-Fetal Medicine Units Network. Low-risk nulliparous women who were at 38 weeks 0 days to 38 weeks 6 days of gestation to labor induction at 39 weeks 0 days to 39 weeks 4 days or to expectant management.
The primary outcome was a composite of adverse perinatal events, which included perinatal death, newborn’s need for respiratory support, Apgar ≤3 at 5 minutes, seizures, infection (confirmed sepsis or pneumonia), birth trauma (injury) or hemorrhage, meconium aspiration syndrome and other birth complications.
The major secondary outcome was cesarean delivery.
The primary outcome occurred in 4.4% of the induced labor group and 5.4% of the expectant management group, a difference that was not statistically significant. However, the percentage of women delivering by cesarean section was significantly lower in the induced group (18.6%) compared to women in the expectant management group (22.2%). Similarly, the frequency of adverse maternal outcomes of preeclampsia or gestational hypertension was much lower in the induced group vs expectant management group; 9.1% vs 14.1%, respectively.
Women in the induced group also delivered significantly earlier than those in the expectant management group (39.3 weeks vs 40.0 weeks).
These findings challenge the traditionally held belief that inducing labor increases the risk of cesarean delivery and present a new option. However, the authors caution that this is not a standard recommendation. They estimate that one cesarean delivery could be avoided for every 28 low-risk, first-time mothers undergoing elective induction at 39 weeks.
These results were presented at the Society for Maternal-Fetal Medicines Annual Pregnancy Meeting in Dallas and published August 9, 2018 in the New England Journal of Medicine.
(Source: NIH, NEJM, American Journal of Obstetrics & Gynecology)