A variety of
oxytocin regimens are used for
labor induction and augmentation. Considering the increasing rates of
labor induction, it is important to assess the most optimal
oxytocin regimen without compromising maternal and fetal safety. The aim of this study was to compare delivery outcomes of low-dose and high-dose
oxytocin induction protocols. This retrospective cohort study of 487 women comparing low-dose
oxytocin protocol (n = 280) and high-dose
oxytocin protocol (n = 207) in
labor induction following cervical ripening by balloon
catheter was performed in Helsinki University Hospital after implementation of a new
oxytocin induction protocol. The study included two six-month cohorts from 2016 and 2019. Women with vital singleton pregnancies ≥37 gestational weeks, cephalic presentation, and intact amniotic membranes were included. The primary outcome was the rate of vaginal delivery. The secondary outcomes were the rates of maternal and neonatal
infections,
postpartum hemorrhage, umbilical artery blood pH-value, admission to
neonatal intensive care, and induction-to-delivery interval. Statistical analyses were performed by using IBM SPSS Statistics for Windows (Armonk, NY, USA). The rate of vaginal delivery was higher [69.9% (n = 144) vs. 47.9% (n = 134); p<0.004] and the rates of maternal and neonatal
infection were lower during the new high-dose
oxytocin protocol [maternal
infections 13.6% (n = 28) vs. 22.1% (n = 62); p = 0.02 and neonatal
infection 2.9% (n = 6) vs. 14.6% (n = 41); p<0.001, respectively]. The rates of post-partum
hemorrhage, umbilical artery blood pH-value <7.05 or
neonatal intensive care admissions did not differ between the cohorts. The median induction-to-delivery interval was shorter in the new protocol [32.0 h (IQR 18.5-42.7) vs. 37.9 h (IQR 27.8-52.8); p<0.001]. In conclusion, implementation of the new continuous high-dose
oxytocin protocol resulted in higher rate of vaginal delivery and lower rate of maternal and neonatal
infections. Our experience supports the use of high-dose continuous
oxytocin induction regimen with a practice of stopping
oxytocin once active labor is achieved, and a 15-18-hour maximum duration for
oxytocin induction in the latent phase of labor following cervical ripening with a balloon
catheter.