Role of mifepristone in pre-induction cervical ripening: a double blind placebo-controlled study

Abstract

Background: Mifepristone has been used for cervical priming and labour induction for long with modest success. This double-blind study compares mifepristone with placebo in causing cervical ripening and inducing spontaneous labour in women past their expected date of delivery.Methods: 200 women at 40 weeks gestation received mifepristone or placebo after Bishop score was assessed. 48 hours later, cervical score was rechecked. Improvement in Bishop score was noted as primary outcome measure. Incidence of spontaneous labour, cesarean delivery and meconium staining of liquor during labour was also monitored.Results: 16 women went into labour before 48 hours and 184 were evaluable. Improvement in Bishop score was noted in significantly more women in mifepristone group (82/94 versus 42/90, p<0.0001). Mean change in Bishop score was 3.22 in mifepristone group and 1.61 in placebo group. This advantage in cervical ripening with mifepristone did not translate into better obstetric outcome. The incidence of spontaneous labour (64/94 mifepristone versus 60/90 placebo), cesarean section (4/94 versus 12/90) and MSL (8/94 versus 10/90) was comparable in the two groups and did not reach statistical significance.Conclusions: Mifepristone has a beneficial effect on cervical ripening in term pregnancies but does not offer obstetric advantage in terms of higher rates of spontaneous labour or vaginal delivery.