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

OBJECTIVE: This study was undertaken to examine associations between induct ion of labor and maternal and neonatal outcomes among women without an iden tified indication for induction. STUDY DESIGN: This was a population-based cohort study of 2886 women with i nduced labor and 9648 women with spontaneous labor who were delivered at 37 to 41 weeks' gestation, all without identified medical and obstetric indic ations for induction. RESULTS: Among nulliparous women 19% of women with induced labor versus 10% of those with spontaneous labor underwent cesarean delivery (adjusted rela tive risk, 1.77; 95% confidence interval, 1.50-2.08). No association was se en in multiparous women (relative risk, 1.07; 95% confidence interval, 0.81 -1.39). Among all women induction was associated with modest increases in i nstrumental delivery (19% vs 15%; relative risk, 1.20; 95% confidence inter val, 1.09-1.32) and shoulder dystocia (3.0% vs 1.7%; relative risk, 1.32; 9 5% confidence interval, 1.02-1.69). CONCLUSION: Among women who lacked an identified indication for induction o f labor, induction was associated with increased likelihood of cesarean del ivery for nulliparous but not multiparous women and with modest increases i n the risk of instrumental delivery and shoulder dystocia for all women.