Induction of labor in women with prior cesarean section: outcomes in a selected low-risk population.

PURPOSE: To investigate the impact of a previous cesarean section on maternal and perinatal outcomes in term pregnancies undergoing labor induction.

METHODS

In this retrospective cohort study, women with singleton, low-risk term pregnancies and labor induction were compared according to the presence or absence of a previous cesarean delivery. The primary outcome was a composite of adverse maternal and perinatal events. Secondary outcomes included cesarean section rate, mode of vaginal delivery, and specific maternal or neonatal complications.

RESULTS

The rate of composite adverse outcomes was comparable between groups (21.9% vs. 23.7%, p = 0.4826). However, placental abruption (1.3% vs. 0.3%, p = 0.0251), suspected triple I (1.9% vs. 0.4%, p = 0.0040), and shoulder dystocia (2.3% vs. 0.8%, p = 0.0265) occurred more frequently in women with a previous cesarean section. Abnormal cardiotocography (27.1% vs. 20.4%, p = 0.0058), operative vaginal delivery (17.8% vs. 11.9%, p = 0.0052), umbilical artery pH < 7.10 (4.9% vs. 2.8%, p = 0.0381), and the need for fetal blood sampling (8.7% vs. 5.0%, p = 0.0055) were also more common in this group. There was no difference in neonatal unit transfer (10.0% vs. 11.5%, p = 0.4328) or low Apgar scores (< 5 at 5 min: 0.3% vs. 0.4%, p = 1.0000). Cesarean section rates were similar (14.8% vs. 14.9%, p = 0.9692). In multivariable analysis, absence of prior vaginal delivery (OR = 3.460, p < 0.0001), higher maternal BMI (OR = 1.038, p < 0.0001), and older maternal age (OR = 1.033, p = 0.0002) were independently associated with adverse outcomes, whereas previous cesarean section was not.

CONCLUSION

Labor induction in women with a prior cesarean section was not associated with increased risk for composite adverse maternal or perinatal outcomes. Nonetheless, TOLAC should be conducted in settings with immediate access to obstetric and neonatal intervention.