Optimal dose of vaginal misoprostol for cervical priming

Abstract

Worldwide, vacuum aspiration is the method of choice for terminating first-trimester unwanted pregnancies, but complications arising from forceful mechanical cervical dilatation prior to suction evacuation are an important cause of maternal morbidity and mortality with first-trimester pregnancy termination. In order to minimize these risks, prostaglandins have been used to prime the cervix before vacuum aspiration. However logistics of storage and their high cost make such prostaglandin preparations beyond the reach of many health care systems. Misoprostol, a synthetic prostaglandin analogue, has been increasingly used in recent years for cervical priming prior to vacuum aspiration as it has the advantages of being cheap, easy to store and easy to use. With increasing use it is thus necessary to determine the optimal route, interval and dose for maximal efficacy. In a prospective double blind study, 120 women were assigned randomly to receive 200 400 600 or 800 μg of misoprostol vaginally. Vacuum aspiration was performed 3-4 h after insertion of the misoprostol. The results of this study show that the use of 400 μg of intravaginal misoprostol with an evacuation time interval of 3-4 h is the clinically optimal dose for pre-operative cervical priming before vacuum aspiration in first-trimester nulliparae, with minimal side effects and risks.