Preinduction cervical ripening: prostaglandin E2 gel vs hygroscopic mechanical dilator.

Objectives: To evaluate the efficacy and safety of hygroscopic mechanical dilators (Dilapan) for ripening the pregnant cervix prior to induction of labour at or near term and to compare it with an intracervical PGE2 gel (Prepidil).

Methods: One hundred and eighty-five women (69 nulliparae, 116 multiparae) at term with singleton pregnancies in cephalic presentation, who were scheduled for induction of labour in the labour ward at the National University Hospital, but had an unfavourable cervical score were randomized into 2 groups by random number table. In group 1 (Prepidil), 0.5 mg of PGE2 in 2.5 ml of triacetin gel was inserted into the endocervical canal. In women in group 2 (Dilapan) upto a maximum of 4 hygroscopic dilators were placed in the endocervical canal. If labour did not ensue at the end of 12 hours of ripening, the cervical score was assessed, amniotomy was performed and oxytocin commenced. Neonatal and obstetric outcome was compared, statistical analysis performed using Chi-square, and t-tests.

Results: Significantly more women in the group who received Dilapan for cervical ripening required amniotomy and oxytocin for induction of labour > 12 hours after priming compared with the group who received Prepidil (p < 0.001). Operative delivery for no progress and fetal distress respectively was similar in the 2 groups. The number of cases of hyperstimulation were higher in the Prepidil group but did not result in an increased incidence of operative deliveries for fetal distress. There was one neonatal death and one case of neonatal sepsis in the Dilapan group. Uterine rupture occurred in 1 woman who received Prepidil.

Conclusion: Dilapan, a mechanical method of cervical ripening is as effective as the more widely accepted mode of ripening with an endocervical PGE2 gel in achieving vaginal delivery. Dilapan would be useful for cervical priming prior to induction of labour in places where prostaglandins are not available because of cost and the need for a cold chain.