OBJECTIVE: To test the association of elective induction of labor at term compared with expectant management and maternal and neonatal outcomes.
METHODS: This was a retrospective cohort study of all deliveries without prior cesarean delivery in California in 2006 using linked hospital discharge and vital statistics data. We compared elective induction at each term gestational age (37–40 weeks) as defined by The Joint Commission with expectant management in vertex, nonanomalous, singleton deliveries. We used multivariable logistic regression to test the association of elective induction and cesarean delivery, operative vaginal delivery, maternal third- or fourth-degree lacerations, perinatal death, neonatal intensive care unit admission, respiratory distress, shoulder dystocia, hyperbilirubinemia, and macrosomia (birth weight greater than 4,000 g) at each gestational week, stratified by parity.
RESULTS: The cesarean delivery rate was 16%, perinatal mortality was 0.2%, and neonatal intensive care unit admission was 6.2% (N=362,154). The odds of cesarean delivery were lower among women with elective induction compared with expectant management across all gestational ages and parity (37 weeks [odds ratio (OR) 0.44, 95% confidence interval (CI) 0.34–0.57], 38 weeks [OR 0.43, 95% CI 0.38–0.50], 39 weeks [OR 0.46, 95% CI 0.41–0.52], 40 weeks [OR 0.57, CI 0.50–0.65]). Elective induction was not associated with increased odds of severe lacerations, operative vaginal delivery, perinatal death, neonatal intensive care unit admission, respiratory distress, shoulder dystocia, or macrosomia at any term gestational age. Elective induction was associated with increased odds of hyperbilirubinemia at 37 and 38 weeks of gestation and shoulder dystocia at 39 weeks of gestation.
CONCLUSION: Elective induction of labor is associated with decreased odds of cesarean delivery when compared with expectant management.
LEVEL OF EVIDENCE: II
Induction without medical indication is associated with reduced odds of cesarean delivery among both nulliparous and multiparous women at each week of term gestation.
Oregon Health & Science University, Portland, Oregon; the University of California, San Francisco, San Francisco, California; Penn State University College of Medicine, Hershey, Pennsylvania; Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; the Group Health Research Institute, Seattle, Washington; and Kaiser Permanente Southern California, Pasadena, California.
Corresponding author: Blair G. Darney, PhD, MPH, Post-Doctoral Fellow, Department of Medical Informatics and Clinical Epidemiology, Department of Obstetrics & Gynecology, Oregon Health & Science University, Mail Code L-466, 3181 SW Sam Jackson Park Road, Portland, OR 97239; e-mail: firstname.lastname@example.org.
Dr. Darney was supported by an Agency for Healthcare Research and Quality T32 postdoctoral award (HS017582). Dr Dublin was supported by National Institute on Aging grant K23AG028954. Drs. Caughey and Snowden were supported by a Health Resources and Services Administration/Maternal and Child Health grant R40MC25694-01-00. Dr. Cheng is supported by the University of California, San Francisco Women's Reproductive Health Research Career Development Award, National Institutes of Health, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (K12 HD001262).
Presented in part at the 2013 Society of Maternal-Fetal Medicine annual meeting, February 11–16, 2013, San Francisco, California.
Financial Disclosure The authors did not report any potential conflicts of interest.