Objective: To estimate whether adding oxytocin to transcervical Foley catheter preinduction cervical ripening improves induction success.
Methods: This trial enrolled 200 women with singleton pregnancies presenting for preinduction ripening. Patients were randomly assigned to receive either Foley catheter alone (control) or Foley catheter plus low-dose oxytocin (treatment). Providers were not blinded to use of oxytocin, and labor was managed according to routine obstetric protocols. This study was powered to detect a 20% difference in the proportion of patients delivered within 24 hours. Secondary outcomes were related to vaginal delivery rate, duration of induction, complications, and pain management.
Results: Results were available for 183 (92 treatment, 91 control) of 200 patients randomly assigned. There were no differences in proportions of deliveries-overall (65% compared with 60%; relative risk [RR] 1.08, 95% confidence interval [CI] 0.86-1.35, number needed to treat 21) or vaginal (48% compared with 46%; RR 1.04, 95% CI 0.76-1.41, number needed to treat 60)-in 24 hours, or cesarean deliveries or times to deliveries between treatment or control groups. Rates of complications were comparable; however, the treatment group had a higher proportion of regional analgesia requirement during induction than controls (23% compared with 9%, P=.01; RR 2.60, 95% CI 1.21-5.56).
Conclusion: Addition of oxytocin to transcervical Foley catheter does not shorten the time to delivery and has no effect on the likelihood of delivery within 24 hours or vaginal delivery rate, although there is an increased use of analgesia by these patients during ripening. The use of oxytocin in addition to Foley catheter ripening is not justified.
Clinical trial registration: ClinicalTrials.gov, www.clinicaltrials.gov, NCT00468520.
Level of evidence: I.