Pre-abortion treatment with a single vaginal suppository containing 9-deoxo-16,16-dimethyl-9-methylene PGE2 in late first and early second trimester pregnancies.

In the present study the efficacy of a new stable prostaglandin E analogue, 9-deoxo-16,16-dimethyl-9-methylene-PGE2 (9-methylene-PGE2), administered as a single vaginal suppository for preoperative dilatation of the cervical canal was evaluated in 382 mainly nulliparous patients. Late first trimester patients received either 20 mg 3 hours prior to or 30 mg 12 hours prior to vacuum aspiration. Early second-trimester patients received 40 mg of the analogue and vacuum aspiration was performed 12 hours later. The degree of cervical dilatation was related to the pretreatment time and the dose of 9-methylene-PGE2. However, even with 20 mg of the analogue and 3 hours pretreatment time, cervical dilatation was adequate in almost 40% of the patients and in the remaining women further mechanical dilatation was regularly performed with ease. The frequency of gastro-intestinal side effects was significantly lower than that found for comparable doses of 15-methyl-PGF2 alpha methyl ester administered by the same route. With 20 mg 9-methylene PGE2, side effects were very rare; only 9% of the patients experienced occasional episodes of vomiting. Three hours' pretreatment with 20 mg of the analogue seems suitable for late first trimester pregnant women in whom the abortion is performed on an outpatient basis. For early second trimester patients pretreatment with 40 mg 9-methylene-PGE2 for 12 hours followed by vacuum aspiration seems to be a better alternative than the two-stage procedures in current use.