A randomized comparison of extra-amniotic saline infusion and intracervical dinoprostone gel for cervical ripening

To compare extra-amniotic saline infusion to intracervical dinoprostone gel for preinduction cervical ripening.

Women with Bishop scores less than 5 were assigned randomly to either extra-amniotic saline infusion (n = 26) or intracervical dinoprostone gel (n = 26) for preinduction cervical ripening. A sample size of 50 would have 80% power to detect a 10-hour difference in the mean time from start of cervical ripening to delivery for the two methods of intervention, with a type I error of .05.

The study populations were similar in age, gestational age, and initial Bishop score. They differed in parity, with 22 nulliparas in the extra-amniotic saline infusion group versus 13 in the dinoprostone gel group (relative risk [RR] 1.69, 95% confidence interval [CI] 1.11, 2.57). The number of women achieving a favorable Bishop score at 6 hours was greater with extra-amniotic saline infusion (n = 20) than dinoprostone gel (n = 9) (RR 2.14, 95% CI 1.22, 3.75). Mean time from start of ripening to delivery was 25.9 hours with extra-amniotic saline infusion and 30.2 hours with dinoprostone gel (P = .25). Birth weight, Apgar scores, umbilical artery pH, and infectious morbidity were similar between groups.

More women achieved a favorable Bishop score at 6 and 12 hours after the start of cervical ripening with extra-amniotic saline infusion compared with dinoprostone gel. Saline infusion is as safe as dinoprostone gel for preinduction cervical ripening.