Low-risk pregnant women whose labor is induced at term might have no higher risk of cesarean delivery than women who deliver later, a large retrospective study suggests.
In fact, perinatal outcomes may be improved.
In a September 21 online paper in the American Journal of Obstetrics and Gynecology, Dr. Yvonne W. Cheng of the University of California, San Francisco, and colleagues note that induction at term is among the most common obstetric interventions in the US. The procedure is currently used in almost a quarter of live births, a doubling in frequency since the 1990s.
Some studies have suggested that such an approach may increase the chances of cesarean section, but there is little definitive information on the risks for low-risk nulliparous women carrying singletons.
To investigate further, the team examined data on more than 440,000 women, mostly between the ages of 20 and 34. They looked only at uncomplicated cases: no chronic hypertension, no gestational or pregestational diabetes, no placenta previa.
“We sought to identify women undergoing elective induction,” the authors wrote.
Compared to women induced at 39 weeks, those who delivered at 40, 41 or 42 weeks did not have a lower incidence of cesarean section (26.2% vs 28.4%).
In fact, on adjusted analysis there was a reduced risk of cesarean in the induction group (odds ratio, 0.90). There was no difference in the risk of operative vaginal delivery (including forceps or vacuum-assisted vaginal delivery) between induction at 39 weeks and delivery later (14.3% vs 12.9%).
In addition, the adjusted odds of meconium aspiration were significantly lower for induction at 39 weeks compared to expectant management (odds ratio, 0.30). There was also a lower risk of a five-minute Apgar score below 7 in the induction group.
The researchers conclude that the study “supports that induction may provide improved perinatal outcomes.”
However, given its retrospective observational nature, “future large prospective, randomized, clinical trials are necessary to further assess the potential benefit in the low-risk population in such a clinical setting.”
Dr. Cheng did not respond to requests for comments.
Am J Obstet Gynecol 2012.
– Reuters Health Information0