Six vs 12 hours of Foley catheter balloon placement in the labor induction of multiparas with unfavorable cervixes: a randomized controlled trial

Abstract

Planned 6- vs 12-hour placement of the double-balloon catheter for cervical ripening in labor induction hastens delivery. The Foley catheter is low-priced and typically performs at least as well as the proprietary double-balloon devices in labor induction. Maternal satisfaction with labor induction is usually inversely related to the speed of the process. This study aimed to compare Foley balloon placement for 6 vs 12 hours in the labor induction of multiparas with unfavorable cervixes. A randomized controlled trial was conducted in a university hospital in Malaysia from January to October of 2022. Eligible multiparous women admitted for induction of labor for various indications were enrolled. Participant inclusion criteria were multiparity (at least 1 previous vaginal delivery of ≥24 weeks' gestation), age ≥18 years, term pregnancy >37 weeks' gestation, singleton pregnancy, cephalic presentation, intact membranes, normal fetal heart rate tracing, no significant contractions (< 2 in 10 minutes), and unfavorable cervix (Bishop score < 6). Participants were randomized after successful Foley balloon insertion for the balloon to be left in place for 6 or 12 hours of passive ripening before removal to check cervical suitability for amniotomy. The primary outcomes were the induction-to-delivery interval and maternal satisfaction with the allocated intervention assessed using a visual numerical rating scale (0-10). Secondary outcomes were derived in part from the core outcome set for trials on induction of labor (Core Outcomes in Women's and Newborn Health [CROWN]). Maternal outcomes were change in first Bishop score after intervention, use of additional method for cervical ripening, time to delivery after balloon removal, mode of delivery, indication for cesarean delivery, duration of oxytocin infusion, blood loss during delivery, presence of third- or fourth-degree perineal tear, maternal infection, use of regional analgesia in labor, length of hospital stay, intensive care unit (ICU) admission, cardiorespiratory arrest, and need for hysterectomy. The secondary neonatal outcomes were Apgar score at 1 and 5 minutes, neonatal intensive care unit (NICU) admission, cord blood pH, neonatal sepsis, birthweight, birth trauma, hypoxic-ischemic encephalopathy, or need for therapeutic hypothermia. Analyses were conducted with the t-test, Mann-Whitney U test, chi-square test, and Fisher exact test, as appropriate. A total of 220 women were randomized (110 to each intervention). Regarding the 2 primary outcomes, the induction-to-delivery intervals were a median (interquartile range) of 15.9 (12.0-24.0) and 21.6 (17.3-26.0) hours (P<.001), and maternal satisfaction scores were 7 (6-8) and 7 (6-8) (P=.734) for 6- and 12-hour placement, respectively. The following rates were observed for 6- and 12-hour placement, respectively: sequential use of additional cervical ripening agent (Foley reinsertion)-29 per 110 (26.4%) and 13 per 110 (11.8%) (relative risk, 2.23; 95% confidence interval, 1.23-4.10; P=.006); spontaneous balloon expulsion-22 per 110 (20.0%) and 37 per 110 (33.6%) (relative risk, 0.60; 95% confidence interval, 0.38-0.94; P=.022); and recommendation of the allocated intervention to a friend-61 per 110 (73.6%) and 87 per 110 (79.1%) (relative risk, 0.90; 95% confidence interval, 0.80-1.08; P=.341). Other secondary outcomes, including cesarean delivery, were not significantly different. Foley balloon placement for 6 hours for cervical ripening in parous women hastens birth but does not increase maternal satisfaction relative to 12-hour placement. Foley reinsertion for additional ripening was more frequent in the 6-hour group.