Preinduction cervical ripening - A randomized trial of intravaginal misoprostol alone vs. a combination of transcervical Foley balloon and intravaginal misoprostol

OBJECTIVE: To determine if the addition of a mechanical ripening agent (tra nscervical Foley balloon) to a pharmacologic agent (intravaginal misoprosto l) improves the efficiency of preinduction cervical ripening. STUDY DESIGN: Singleton patients with an indication for delivery, unfavorab le cervix (Bishop score less than or equal to5) and no contraindication to labor were randomly assigned to two groups: misoprostol alone (25 mug intra vaginally every 3 hours for no more than 12 hr) or combination therapy (25- French transcervical Foley balloon inflated to 50 mL of sterile water with identical intravaginal misoprostol dosing). All patients received a history and physical examination (including Bishop score), preripening ultrasound, electronic fetal heart rate and contraction monitoring (to rule out sponta neous labor and document fetal well-being). Multiple variables of perinatal outcome were analyzed, including the main outcome variables of ripening-to -delivery time and cesarean section rate. RESULTS: During, August 1998 to August 1999, 81 patients were randomized, 4 0 to misoprostol alone and 41 to combination therapy. There were no differe nces between the groups with respect to maternal demographics, preripening Bishop score, maternal complications, intrapartum intervention or neonatal outcome. The misoprostol group spent longer periods of time in active labor , and there was a trend for the combination group to require oxytocin for l onger intervals. These findings did not significantly affect the total ripe ning-to-delivery time or cesarean section, rate which were similar for both groups. CONCLUSION. The addition of mechanical ripening with a transcervical Foley balloon to intravaginal misoprostol did not improve the efficiency of prein duction cervical ripening. Mechanical and pharmacologic cervical ripening a gents appear to act independently rather than synergistically.