Pre-induction cervical ripening: a randomized comparison of two methods

Abstract

Objectives: To compare two methods of pre-induction cervical ripening in a randomized clinical trial.

Methods: A single intracervical prostaglandin E2 (PGE2) gel application was compared with a single insertion of hygroscopic dilators in 441 women at term with unfavorable cervical scores. Induction success was defined as entry into active labor within 6 hours of oxytocin infusion.

Results: There was no statistical difference in pre- or post-ripening cervical scores. In the group receiving hygroscopic dilators, only 28% entered the active phase of labor within 6 hours of oxytocin infusion compared with 45% (P < .001) in the PGE2 group. Thus, in this study, a change in cervical score did not directly predict induction success. There was a higher rate of postpartum endometritis (24 versus 14%; P = .007) and suspected neonatal infection (10 versus 5%; P = .03) in the dilator group.

Conclusions: Pre-induction ripening by hygroscopic dilators and intracervical PGE2 was equivalent as measured by changes in the cervical score. The change in cervical score, however, was not predictive of successful induction, and PGE2 was more frequently associated with induction success. Hygroscopic dilators were associated with a higher incidence of postpartum maternal and neonatal infection because of a longer duration of labor. Hospital charges for intracervical PGE2 gel totaled $522 compared with $91 for the insertion of three dilators.