Induction of labor and the relationship to cesarean delivery: A review of 7001 consecutive inductions.

OBJECTIVE: The goal of this project was to study the increasing risk of induction of labor in a community hospital and to determine whether it had an adverse effect on the rate of cesarean delivery.

STUDY DESIGN: From January 1, 1990, through July 31, 1997, 18,055 consecutive singleton pregnancies in women who were candidates for labor were reviewed via a comprehensive perinatal database. The risk of and indication for induction were reviewed. Cesarean delivery rates were calculated for nulliparous and multiparous patients by indication for induction and were compared with rates for patients who had spontaneous labor. Overall trends in cesarean delivery were reviewed for the duration of the study period.

RESULTS: The annual induction rate significantly rose from 32% to 43% at the conclusion of the study period. Labor was induced in nearly 40% of nulliparous patients. Postdate pregnancy was the most common indication for induction, although few patients were at or beyond 42 weeks' gestation. The cesarean delivery rate remained at or below 20% for the years of the study. No increase was noted in spite of the increasing risk of induction. However, for nulliparous patients who had elective induction of labor, the risk of cesarean delivery was twice that of nulliparous patients who had spontaneous labor.

CONCLUSION: The use of induction methods has significantly increased in this community hospital. More than 40% of patients are now candidates for induction. The cesarean delivery rate remains low in this facility in spite of a marked increase in risk of operative delivery for nulliparous patients who undergo induction.