Induction of labour: a comparison between controlled-release dinoprostone vaginal pessary (Cervidil) and dinoprostone intravaginal gel (Prostin E2).

BACKGROUND: There are various prostaglandin preparations available for inducing labour. Controlled-release dinoprostone vaginal pessary is used in a number of centres in Australia and New Zealand.

AIMS: To compare the efficacy and safety of controlled-release dinoprostone vaginal pessary (Cervidil) with dinoprostone intravaginal gel (Prostin E2) for induction of labour.

METHODS: Retrospective cohort study of 969 women who were induced using either 10-mg controlled-released dinoprostone vaginal pessary (n=507) or intravaginal dinoprostone gel (n=462) at National Women's Health, Auckland City Hospital. Study outcomes included induction to delivery interval, mode of delivery, rate of oxytocin augmentation and incidence of uterine hyperstimulation.

RESULTS: Induction to vaginal birth interval was longer among nullipara receiving the pessary compared to those receiving intravaginal gel (21.5 vs 17.8 h, P=0.004). There was no difference in rates of oxytocin augmentation or in mode of birth between pessary and gel groups. There was a trend to more uterine hyperstimulation among women induced with the pessary compared with those induced with intravaginal gel (22 (4.5%) vs 11 (2.4%) relative risk (RR) 1.9 (0.9-3.9)). Hyperstimulation associated with an abnormal fetal heart pattern (14 (2.9%) vs 2 (0.4%), RR 6.5 (1.5-28.9)) or treated with tocolytics (9 (1.8%) vs 1 (0.2%), RR 8.4 (1.1-66)) was more common in women who received the pessary.

CONCLUSION: Use of dinoprostone vaginal pessaries did not shorten time to delivery or improve any other birth outcome measured compared to dinoprostone intravaginal gel. Clinically significant hyperstimulation appeared more common following use of the pessary. Large randomised controlled trials are needed to confirm or refute these findings.