Mifepristone and vaginal misoprostol are effective, acceptable and inexpensive medical abortion regimen

Vaginal administration of misoprostol after mifepristone is more effective than oral administration at inducing first-trimester abortion and is associated with somewhat fewer side effects. The incidence of continued pregnancy is lower, and abortion is less likely to require surgical intervention and tends to take less time with vaginal than oral administration of the prostaglandin analog, according to results of a comparative study.(1) A second study confirms the effectiveness of mifepristone followed by vaginal misoprostol, adding that this combination is considerably less costly than the standard medical abortion regimen of mifepristone and gemeprost.(2)

The first study, conducted at a fertility control clinic in Scotland between June 1993 and January 1994, was a prospective, randomized trial involving 270 women requesting an abortion 35-63 days after their last menstrual period. Gestation was determined by ultrasound, and women with a suspected ectopic pregnancy or contraindications to mifepristone were excluded.

The women were given 600 mg of mifepristone and allowed to go home. They returned to the clinic 348 hours later, at which time they were randomly assigned to receive 800 mcg of misoprostol either orally or vaginally. After four hours, a manual vaginal examination was performed to determine whether the fetus had been expelled from the uterus; the women we observed for another four hours, then were given an appointment for a follow-up visit 14 days later and discharged.

Women who did not have an abortion within eight hours had an ultrasound examination at the 14-day follow-up visit, or sooner if they requested it. If the test detected a pregnancy or incomplete abortion, the women underwent vacuum curettage.

Seven of the women had an abortion after receiving the mifepristone but before being given the misoprostol. (They took misoprostol to ensure complete abortion, but were excluded from the analysis.) Of the remaining women, 133 received misoprostol vaginally and 130 received it orally. The two groups were similar with respect to age (a mean of about 26 years), interval since last menstrual period (approximately 50 days) and parity (roughly one-half had never been pregnant).

The women who received misoprostol vaginally were significantly more likely than those who took it orally to have an abortion without requiring surgical intervention (95% vs. 87%; p=.03), and to have an abortion within four hours of receiving the prostaglandin (93% vs. 78%; p=.001). They were also less likely to have a continuing pregnancy (1% vs. 7%;p p=.001)--an important improvement, the archers note, in view of reports of congenital malformations after unsuccessful medical abortions.

Before discharge, 238 women completed a questionnaire about side effects. Overall, gastrointestinal problems (vomiting, diarrhea and nausea) were the most common complaints; other side effects were fatigue, headaches, hot flushes and dizziness. The incidence of vomiting and diarrhea was significantly lower among those given vaginal misoprostol than among those receiving oral misoprostol (31% vs. 44% and 18% vs. 36%, respectively); differences in reports of other side effects and of the severity of side effects were not significant.

One woman who received vaginal misoprostol experienced a hemorrhage serious enough to require transfusion. This complication, although rare, underscores the importance of access to appropriate backup for medical abortion services.

Roughly 80% of women in both groups returned for the follow-up visit; to obtain information about bleeding or other problems experienced by the women who did not return, the researchers contacted these women's physicians. The reported duration of bleeding averaged slightly more than nine days among women in both groups; reductions in hemoglobin levels also were similar for both groups.

The second study, which involved 360 women requesting an abortion at a Scottish hospital within 63 days of their last menstrual period, confirmed the effectiveness of the combined regimen of mifepristone and vaginal misoprostol. Among the 356 women in this group who received the complete regimen of 200 mg of mifepristone and 800 mcg of misoprostol administered vaginally, 96% had a complete abortion without surgical intervention, and 84% had an abortion within six hours of receiving the misoprostol. The researchers note that most of this procedure can be managed by nurses and that the cost is one-fourth that of the standard regimen of mifepristone and gemeprost.

Misoprostol originally attracted attention as a possible component of medical abortion, the first set of investigators point out, because it is less expensive than gemeprost and is designed to be taken orally. According to their studies, when administered vaginally in combination with mifepristone, it also is as effective as gemeprost and highly acceptable. Therefore, the findings suggest, this regimen could improve the feasibility of medical abortion in many parts of the world.

References

1. H. El-Refaey et al., "Induction of Abortion with Mifepristone (RU 486) and Oral or Vaginal Misoprostol," New England Journal of Medicine, 332:98-987, 1995.

2. G. C. Penney et al., "An Effective, Low-Cost Regimen for Early Medical Abortion," British Journal of Family Planning, 21:5-6, 1995.

Copyright The Alan Guttmacher Institute Sep 1995
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