Induction of labour with a viable infant: a randomised clinical trial comparing intravaginal misoprostol and intravaginal dinoprostone.

OBJECTIVE: To compare the efficacy and safety of vaginal misoprostol (50 microg) with vaginal dinoprostone.

DESIGN: Double-blind randomised trial.

SETTING: Obstetrics Department, Poissy Hospital, France.

PARTICIPANTS: 370 patients with medical indications for induction of labour.

OUTCOME MEASURES: Vaginal deliveries within 24 hours, as well as time to vaginal deliveries, caesarean rates, costs, and fetal, neonatal and maternal condition.

RESULTS: Compared with vaginal dinoprostone, vaginal misoprostol resulted in greater efficacy in several areas: vaginal delivery within 24 hours; time to vaginal delivery; and vaginal delivery within 12 hours. There was a non-significant increase in the caesarean section rate for fetal distress in the misoprostol group, but fewer caesarean sections for failed induction. Fetal tolerance was similar in the two groups, although significantly more neonates had a cord pH <7.20 and (non-significantly) none had meconium stained amniotic fluid in the misoprostol group. The incidence of poor neonatal outcome was similar in both groups. Subgroup analysis by indication for induction showed that the higher rates of arterial cord pH <7.20 and of meconium-stained amniotic fluid with misoprostol persisted only in possible fetal compromise. Poor neonatal outcome was less frequent in the misoprostol group in cases of induction for non-fetal indications.

CONCLUSIONS: Vaginal misoprostol resulted in successful and earlier induction of labour more often than dinoprostone, but the safety of misoprostol raises some concern in potentially compromised infants. Misoprostol should be preferred to dinoprostone in cases of induction for non-fetal indications.