The use of misoprostol for pre-operative cervical dilatation prior to vacuum aspiration: a randomized trial

Misoprostol is effective for cervical priming prior to vacuum aspiration fo r first trimester termination of pregnancy. Previous studies showed that th e oral route was more acceptable to patients but there were higher incidenc es of side-effects when compared with the vaginal route, This study is to d etermine the optimal dosage and route of administration of misoprostol for pre-operative cervical dilatation. A double-blind, randomized trial was und ertaken for 225 nulliparous women with 8-12 weeks amenorrhoea, They were ra ndomly assigned to groups given 0 (placebo), 200 or 400 mu g oral or vagina l misoprostol 3 h prior to vacuum aspiration. In misoprostol-treated groups the baseline cervical dilatation was significantly increased when compared with the placebo group; the effect was dose-related in the oral but not in the vaginal group. The cumulative force and blood loss was significantly d ecreased in the misoprostol-treated groups. The incidences of side-effects were more frequent in misoprostol groups but were not related to the route and dosage of medication. The duration of procedure, incidences of post-ope rative complications, the duration of post-operative bleeding and the inter val to the first period were similar in the five treatment groups. We concl ude that a 3 h pre-treatment interval is effective for both oral and vagina l routes. When given orally, 400 mu g is more effective than 200 mu g. The efficacy was otherwise similar when compared with the vaginal route. We rec ommend 400 mu g oral misoprostol 3 h prior to vacuum aspiration for cervica l dilatation.