Previous reports with an 850 micrograms prostaglandin E2 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 PGE2 vaginal film with a nonmedicated 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 PGE2 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 PGE2 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 PGE2 group. This study emphasizes the need for a control group when studying the success of agents used for ripening the pregnant cervix at term.