Comparison of elective induction of labor with favorable Bishop scores versus expectant management: a randomized clinical trial

Abstract

Objective: To determine if elective induction (IND) increases the risk of cesarean delivery compared to expectant management (EM).

Methods: A randomized clinical trial involving women 39 weeks' gestation, according to strict dating criteria, with a Bishop score of 5 or more in nulliparous patients and 4 or more in multiparous patients. The control group was expectantly managed and delivered for obstetric indications, but not later than 42 weeks' gestation. The study had 80% power to detect a three-fold increase in cesarean delivery.

Results: One-hundred-and-sixteen patients (45 nulliparous) were randomized to IND and 110 (58 nulliparous) to EM. Demographic characteristics were no different between the groups. The cesarean delivery rate in the IND group was 6.9% (8/116) compared to 7.3% (8/110) in the EM group (p = NS). Rates of cesarean delivery for nulliparous patients randomized to IND compared to EM were also not significantly different: 13.3% (6/45) versus 10.3% (6/58) respectively (p = NS). Neonates delivered of IND patients weighed less than those of the EM group (3459 +/- 347 versus 3604 +/- 438, p = 0.006).

Conclusion: In women with favorable Bishop scores, elective induction of labor resulted in no increase in cesarean delivery compared to expectant management.