Comparison of different prostaglandin analogues and laminaria for preoperative dilatation of the cervix in late first trimester abortion.

The present study included 550 mainly primiparous women in the 8th to 12th week of pregnancy admitted to the hospital for termination of pregnancy. The patients were treated by different prostaglandin analogues or one medium size laminaria tent followed by vacuum aspiration. The treatment period was three hours, which for some analogues was extended to six and twelve hours. The prostaglandins studied were 15-methyl PGF2 alpha methyl ester (0.5 and 1.0 mg), 16,16-dimethyl-trans-delta 2 PGE1 methyl ester (1.0 mg), 9-deoxo-16,16-dimethyl-9-methylene PGE2 (30 mg), all administered by the vaginal route, and 16-phenoxy-omega-17,18, 19,20-tetranor PGE2 methyl sulfonylamide (0.25 and 0.5 mg) given as i.m. injections. At operation the degree of cervical dilatation, the amount of blood loss and other operative complications were registered. The patients were continuously supervised during treatment and during at least three hours after operation. Side effects, complications and vital signs were recorded. The degree of cervical dilatation was related to the duration of prostaglandin treatment. If the duration of prostaglandin treatment was prolonged, the frequency of gastrointestinal side effects, abortion prior to scheduled time for vacuum aspiration and pain needing analgesic treatment also increased. Both the efficacy and the frequency of side effects were dose dependent. The outcome of therapy after three-hour pretreatment was evaluated. All the prostaglandins were more effective than one medium size laminaria tent in dilating the cervical canal. The three E analogues were most effective. The number of patients with bleeding at operation of 50 ml or more was also higher following laminaria than following prostaglandin pretreatment. Most advantageous in this respect were the three E analogues. Frequency of gastrointestinal side effects and degree of pain following 9-methylene PGE2 and 16,16-dimethyl PGE1 methyl ester was the same as following laminaria treatment.