Outpatient balloon catheter vs inpatient prostaglandin for induction of labor: a randomized trial

Approximately 1 in 4 pregnant women undergo induction of labor. Meta-analyses have shown that mechanical methods of induction of labor are safe and effective, as is starting induction in an outpatient setting. However, few studies have evaluated outpatient balloon catheter induction in comparison with pharmacologic methods.

This study aimed to determine whether women who underwent outpatient induction of labor with a balloon catheter would have a lower cesarean delivery rate than women who underwent inpatient induction of labor with vaginal prostaglandin E2 without an increase in adverse maternal or neonatal events.

This was a superiority randomized controlled trial. The eligibility criteria were pregnant women (nullipara and multipara) with a live singleton fetus in vertex presentation with any medical comorbidity who underwent planned induction of labor at term and who had an initial modified Bishop Score of 0 to 6 at 1 of 11 public maternity hospitals in New Zealand. The intervention groups were outpatient single balloon catheter induction in comparison with inpatient vaginal prostaglandin E2 induction. The primary hypothesis was that participants who started their induction at home with a balloon catheter would have a lower risk for cesarean delivery than participants who started their induction with prostaglandins and remained in hospital throughout. The primary outcome was cesarean delivery rate. Participants were randomized using a centralized secure online randomization website in a 1:1 ratio, stratified by parity and hospital. The participants and outcome assessors were not blinded to group allocation. An intention-to-treat analysis with adjustment for stratification variables was used.

A total of 539 participants were randomized to outpatient balloon catheter induction, and 548 participants were randomized to inpatient prostaglandin induction; the mode of birth was reported for all participants. The cesarean delivery rate was 41.0% among participants allocated to outpatient balloon induction and 35.2% among those allocated to inpatient prostaglandin induction (adjusted odds ratio, 1.27; 95% confidence interval, 0.98-1.65). Women in the outpatient balloon catheter group were more likely to have artificial rupture of membranes and to received oxytocin and an epidural. No differences were found in the rates of adverse maternal or neonatal events.

Outpatient balloon catheter induction was not found to reduce the cesarean delivery rate when compared with inpatient vaginal prostaglandin E2 induction. The use of balloon catheters in an outpatient setting does not seem to increase the rate of adverse events for mothers or babies and can be offered routinely.