A randomized trial of 2 regimens for the administration of vaginal prostaglandins (gemeprost) for the induction of midtrimester abortion.

The most frequently used method for second trimester termination of pregnancy is administration of gemeprost (16, 16-dimethyl-trans delta 2-prostaglandin E1methyl ester) as a vaginal pessary. This provides a safe and effective method for achieving abortion. The current prescribing advice is to insert the pessaries into the posterior vaginal fornix every 3 hours. This study compares this to a 6-hourly regimen. The median abortion interval in the 6-hour group was shorter than the 3-hour group (15 versus 16 hours respectively) but the cumulative abortion rates were similar (98% in the 3-hour group and 91.8% in the 6-hour group). The 6-hour group required a significantly lower total dose of gemeprost to induce abortion. There was no difference in the rates of side-effects in the 2 groups but those receiving pessaries every 6 hours required less analgesia. This study finds no advantage in giving gemeprost every 3 hours.