Increased single-balloon Foley catheter volume for induction of labor and time to delivery: A systematic review and meta-analysis

INTRODUCTION: Induction of labor is a common intervention. The objective was to investigate whether larger Foley catheter volumes for labor induction decrease the total time from induction to delivery. MATERIAL AND METHODS: Randomized controlled trials comparing larger single-balloon volumes (60-80 mL) during Foley catheter cervical ripening with usual volume (30 mL) in women undergoing labor induction were identified by searching electronic databases (MEDLINE, Scopus, ClinicalTrials.gov, PROSPERO, EMBASE, Scielo and the Cochrane Central Register of Controlled Trials) from inception through 2017. The primary outcome was mean time from induction to delivery in hours. Secondary outcomes included time from induction to vaginal delivery, delivery within 24 h, time to Foley expulsion, cesarean section, chorioamnionitis, epidural use, hemorrhage, meconium staining, and neonatal intensive care unit admission. Meta-analysis was performed using the random effects model of DerSimonian and Laird (PROSPERO CRD42017058885). RESULTS: Seven randomized controlled trials including 1432 singleton gestations were included in the systematic review. Women randomized to larger volumes of balloon had a significantly shorter time from induction to delivery (mean difference 1.97 h, 95% CI -3.88 to -0.06). There was no difference in cesarean section between groups (16 vs. 18%, relative risk 0.84, 95% CI 0.6-1.17). A larger balloon volume was associated with a nonsignificant decrease in time from induction to delivery in multiparous (mean difference 2.67 h, 95% CI -6.1 to 0.76) and nulliparous women (mean difference 1.82 h, 95% CI -4.16 to 0.53). CONCLUSION: Balloon volumes larger than 30 mL during Foley catheter induction reduce total time to delivery by approximately 2 h.