Risk of cesarean delivery after induction at term in nulliparous women with an unfavorable cervix

OBJECTIVE: The purpose of this study was to evaluate the effect of induction on the route of delivery in nulliparous women laboring at term in a community hospital system. STUDY DESIGN: From April 1997 to October 1999, there were 7282 deliveries in nulliparous patients who met inclusion criteria. Cesarean delivery rates were calculated for patients in spontaneous labor and for patients who underwent induction. RESULTS: Among 4635 women (63.7%) in spontaneous labor, the cesarean delivery rate was 11.5% versus 23.7% among the 2647 (36.3%) patients who underwent induction. An important variable that affected the delivery route was the Bishop score at the initiation of the induction. The cesarean delivery rate was 31.5% among patients whose Bishop score was <5 at induction versus 18.1% for patients with a score greater than or equal to5 (P < .001). CONCLUSION: The induction of labor in nulliparous patients, especially those women with an unfavorable cervix as measured by Bishop score, is associated with a significantly increased risk of cesarean delivery.