Maternal and neonatal outcomes after induction of labor without an identified indication.

OBJECTIVE

This study was undertaken to examine associations between induction of labor and maternal and neonatal outcomes among women without an identified indication for induction.

STUDY

DESIGN

This was a population-based cohort study of 2886 women with induced labor and 9648 women with spontaneous labor who were delivered at 37 to 41 weeks' gestation, all without identified medical and obstetric indications for induction.

RESULTS

Among nulliparous women 19% of women with induced labor versus 10% of those with spontaneous labor underwent cesarean delivery (adjusted relative risk, 1.77; 95% confidence interval, 1.50-2.08). No association was seen in multiparous women (relative risk, 1.07; 95% confidence interval, 0. 81-1.39). Among all women induction was associated with modest increases in instrumental delivery (19% vs 15%; relative risk, 1.20; 95% confidence interval, 1.09-1.32) and shoulder dystocia (3.0% vs 1. 7%; relative risk, 1.32; 95% confidence interval, 1.02-1.69).

CONCLUSION

Among women who lacked an identified indication for induction of labor, induction was associated with increased likelihood of cesarean delivery for nulliparous but not multiparous women and with modest increases in the risk of instrumental delivery and shoulder dystocia for all women.