Cervical preparation with 400 mcg of misoprostol significantly reduced complications in women undergoing first-trimester abortion by vacuum aspiration, based on data from a randomized, parallel group trial of nearly 5,000 women published online March 8 in the Lancet.
Inadequate cervical dilation can cause complications during vacuum aspiration procedures, and misoprostol has been shown to increase cervical dilation, said Dr. Olav Meirik and colleagues at the World Health Organization World Bank Special Programme of Research, Development and Research Training in Human Reproduction in Geneva, Switzerland.
"However, no study has been large enough to assess whether cervical preparation with misoprostol is associated with reduced rates of immediate and delayed complications of vacuum aspiration for first-trimester surgical abortion," the researchers said (Lancet 2012 March 8 [doi: 10.1016/S0140-6736(11)61937-5]).
A total of 4,972 women who underwent first-trimester surgical abortions at 14 locations in nine countries were enrolled in the study and randomized to receive two 200-mcg misoprostol tablets or a placebo 3 hours prior to surgery. Complete data were available for 2,427 women in the misoprostol group and 2,431 women in the placebo group. The mean age of the women was 27 years.
After a follow-up period of up to 2 weeks, none of the women who received misoprostol had cervical tears, and three had uterine perforations. By contrast, two women in the control group had cervical tears, and one had a uterine perforation.
On average, the cervical diameter prior to surgery was significantly greater in women who received misoprostol compared with placebo, and the mean duration of vacuum aspiration was significantly shorter in the misoprostol group vs. the placebo group (3.6 minutes vs. 3.9 minutes). Approximately 40% of the misoprostol group needed no additional mechanical cervical dilation, compared with 22% of the placebo group, and the amount of dilation, when needed, was less in the misoprostol group.
The average time between the treatment (or placebo) and the procedure was 3 hours. During this time, side effects including abdominal pain (55% vs. 22%), vaginal bleeding (37% vs. 7%), and nausea (7% vs. 4%) were more frequent in the misoprostol group. However, the researchers noted no differences in the incidence of pelvic inflammatory disease or other serious adverse events between the groups.
Incomplete abortions were significantly less likely in the misoprostol group (less than 1%), compared with the placebo group (2%). Most of these women with incomplete abortions underwent additional uterine re-evacuation.
The study was limited by the lack of total blinding and the lack of power to analyze any specific complications in subgroups of patients, the researchers noted. But the findings suggest that cervical preparation with misoprostol prior to abortion by vacuum aspiration facilitates cervical dilation and reduces overall complications, and "should be considered together with the side effects and with women’s acceptance of the drug regimen," they said.
The researchers said they had had no financial conflicts to disclose. This study was supported by United Nations Development Programme/UN Population Fund/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction, Department of Reproductive Health and Research, WHO, and the Packard Foundation.