Intravaginal misoprostol as a cervical ripening agent.

OBJECTIVE: To determine if misoprostol (exogenous prostaglandin E1 PGE1) used vaginally was of value in improving the Bishop score, leading to an early safe vaginal delivery in women in whom the cervix is unripe and delivery is indicated.

DESIGN: A double-blind clinical trial.

SETTING: Antenatal and labour wards of the University Hospital of the West Indies, Jamaica.

SUBJECTS: Forty-five women in the third trimester with various obstetric indications for induction of labour and with no contra-indications to prostaglandins.

INTERVENTIONS: The women were randomly assigned to receive treatment or a placebo. The treated group had 100 micrograms misoprostol inserted vaginally while the placebo was similarly inserted.

MAIN OUTCOME MEASURES: Efficacy of the misoprostol was measured by the increase in the Bishop score 12 h after giving the treatment, the time between insertion and delivery, the need for oxytocin, and the outcome of the pregnancy.

RESULTS: The prostaglandin was superior to the placebo in ripening the cervix and inducing labour. The change in Bishop score was 5.3 in the misoprostol group compared with 1.5 in the placebo group (P < 0.001). The mean time from insertion to delivery was 15.6 h in the former while it was 43.2 h in the placebo group (P < or = 0.001). The need for oxytocin was also significantly less in the women receiving the prostaglandin compared with those who received the placebo (29% vs 62%, P < 0.02). There was no difference in the two groups in the delivery outcome in terms of complications, Apgar scores and mode of delivery.

CONCLUSIONS: Intravaginal misoprostol is an effective and cheap method of inducing labour in the third trimester.