Induction of labor in late-term pregnancy: amniotomy plus early oxytocin perfusion versus amniotomy plus oxytocin perfusion delayed by 24 h

Objective

To assess the maternal and fetal benefits of delaying oxytocin perfusion by 24 h following labor induction by amniotomy after 41 weeks of gestation (WG).

Methods

We performed a retrospective review including all women with a vertex presentation fetus who had an indication for labor induction by amniotomy with or without oxytocin after 41 WG between 2015 and 2022. Patients who underwent an IOL by amniotomy followed by oxytocin perfusion within 0 to 4 hours (early oxytocin group: EO group) were compared with patients who underwent an IOL by amniotomy alone or followed by an oxytocin perfusion after an expectant period for up to 24 hours in the absence of a spontaneous onset of labor (delayed oxytocin group: DO group). The primary outcome was the rate of vaginal delivery (natural or operative). The secondary outcomes were maternal and neonatal complications.

Results

We included 363 patients: 103 patients in the EO group and 260 in the DO group. Only 47 of the women in the DO group (18 %) required oxytocin. The proportion of vaginal deliveries was significantly higher in the DO group (248 patients, 95.4 %) than in the EO group (85 patients, 82.55 %) (p<0.01). Maternal morbidity did not differ significantly between groups. Fewer babies displayed severe newborn acidemia or required transfer to the neonatal intensive care unit in the DO group (p<0.05).

Conclusion

Delaying oxytocin administration by 24 hours after amniotomy was associated with a significantly higher rate of vaginal delivery. These results required confirmation in prospective randomized studies.