Maternal and Neonatal Outcomes in Nulliparous Participants Undergoing Labor Induction by Cervical Ripening Method

Abstract

Objective This study aimed to evaluate maternal and neonatal outcomes by method of cervical ripening for labor induction among low-risk nulliparous individuals. Study Design This is a secondary analysis of a multicenter randomized trial of labor induction at 39 weeks versus expectant management in low-risk nulliparous participants. Participants undergoing cervical ripening for labor induction in either group were included. Participants were excluded for preripening membrane rupture, abruption, chorioamnionitis, fetal demise, or cervical dilation ≥3.5 cm. Cervical ripening was defined by the initial method used: prostaglandin only (PGE; referent), Foley with concurrent prostaglandin (Foley-PGE), Foley only (Foley), and Foley with concurrent oxytocin (Foley-oxytocin). Coprimary outcomes were adverse maternal and neonatal composites. Secondary outcomes included cesarean delivery and length of labor and delivery (L&D) stay. Multivariable analysis was used to adjust for patient characteristics. Results Of 6,106 participants included in the trial, 2,376 (38.9%) met criteria for this analysis. Of these, 1,247 (52.4%) had cervical ripening with PGE, 290 (12.2%) had Foley-PGE, 385 (16.2%) had Foley, and 454 (19.1%) had Foley-oxytocin. The maternal composite outcome was similar among participants who received Foley-PGE (24.1%, adjusted relative risk [aRR] = 1.21, 95% confidence interval [CI]: 0.96–1.52), Foley (21.3%, aRR = 1.16, 95% CI: 0.92–1.45), or Foley-oxytocin (19.4%, aRR = 1.04, 95% CI: 0.83–1.29), compared with PGE (19.7%). The neonatal composite outcome was less frequent in participants who received the Foley-PGE (2.4%, aRR = 0.35, 95% CI: 0.16–0.75) or Foley (3.6%, aRR = 0.51, 95% CI: 0.29–0.89) but did not reach statistical significance for participants who received Foley-oxytocin (4.6%, aRR = 0.63, 95% CI: 0.40–1.01) compared with PGE only (6.8%). Participants who received Foley-PGE or Foley-oxytocin had a shorter L&D stay (adjusted mean difference = −1.97 hours, 95% CI: −3.45 to −0.49 and −5.92 hours, 95% CI: −7.07 to −4.77, respectively), compared with PGE. Conclusion In term low-risk nulliparous participants, Foley alone or concurrent with PGE is associated with a lower risk of adverse neonatal outcomes than with PGE alone. Length of L&D stay was the shortest with concurrent Foley-oxytocin. Key Points