OBJECTIVES To identify independent risk factors for cesarean delivery after induction of labor (IOL) and to develop a nomogram for predicting cesarean delivery among nulliparous women undergoing IOL at term. METHODS This is a retrospective cohort study including nulliparous women with singleton, term (≥37 0/7 weeks of gestation), cephalic pregnancies undergoing IOL from July 1, 2006, through May 31, 2012, at a tertiary care academic center. Inductions were identified using ICD-9 codes. Demographic, delivery, and outcome data were abstracted manually from the medical record. Women with a contraindication to vaginal delivery (malpresentation, abnormal placentation, prior myomectomy) were excluded. Independent risk factors for cesarean delivery were identified using logistic regression. RESULTS During the study period, there were 785 nulliparous inductions who met study criteria; 231 (29.4%) underwent cesarean delivery. Independent risk factors associated with an increased risk of cesarean delivery included older maternal age, shorter maternal height, greater body mass index, greater weight gain during pregnancy, older gestational age, hypertension, diabetes mellitus, and initial cervical dilation <3 cm. A nomogram was constructed based on the final model with a bias-corrected c-index of 0.709 (95% CI 0.671–0.750). CONCLUSION We identified independent risk factors which can be utilized to predict cesarean delivery among nulliparous women undergoing IOL at term. If validated in other populations, the nomogram could be useful for individualized counseling of women with a combination of identifiable antepartum risk factors.

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