Previous reports with an 850 μg prostaglandin E 2 film for cervical ripening before induction of labour in term pregnancy have been favourable. These studies however had no controls. The present study compares this PGE 2 vaginal film with a non-medicated similar vaginal film (placebo) for preinduction cervical ripening in primigravid women at term. A total of 69 women with modified Bishop's cervical scores 1–5 were assigned randomly to either the PGE 2 group (33 women) or placebo group (36 women). Cervical score assessments were made at 12 and 24 hours after which labour was induced by amniotomy and oxytocin infusion. Although the cervical scores between placebo and PGE 2 groups at 12 and 24 hours were not significantly different, the scores were marginally better with the prostaglandin film. Pregnancy outcome was satisfactory in both groups with no perinatal or maternal mortality and morbidity. The caesarean rate was 30.6% in the placebo group and 24.2% in the PGE 2 group. This study emphasises the need for a control group when studying the success of agents used for ripening the pregnant cervix at term.