Pregnancies that fail in the first trimester—ones that end in embryonic or fetal death or in incomplete spontaneous abortion, ones whose inevitable outcome is spontaneous abortion and ones characterized by the absence of an embryo in the gestational sac—traditionally have been managed with dilation and curettage. However, vaginally administered misoprostol may be an effective alternative to surgery for some women. The odds of successful treatment appear to be greatest for nulliparous women, those who are Rh-negative, and those who have lower abdominal pain or vaginal bleeding within 24 hours before receiving the misoprostol. These are the key findings of a secondary analysis of data from a multicenter study comparing the effectiveness and safety of misoprostol and vacuum aspiration for the treatment of early pregnancy failure.1
Participants in the study, which was conducted at universities in Florida, New York and Pennsylvania in 2002–2004, were randomly assigned to receive medical treatment or vacuum aspiration. Those in the medical treatment group had 800 mcg of misoprostol inserted into the vagina and returned to the study site two days later for a follow-up examination and ultrasound. If clinical signs of pregnancy were still evident, a second dose of misoprostol was administered; if the explusion was not complete five days later, women were offered vacuum aspiration. In telephone interviews 30 days after receiving the first dose of misoprostol, women reported any other treatment they had received since the procedure. The medical regimen was considered successful if explusion occurred within 30 days without the need for surgical intervention.
The analyses included 485 women who received the misoprostol regimen, among whom the overall success rate was 85%. Using results of univariable analysis that identified potential predictors of successful treatment, the researchers conducted logistic regression analysis to determine which ones were statistically significant in a multivariable context. They found that women who had had lower abdominal pain or vaginal bleeding in the 24 hours before receiving the misoprostol had elevated odds of successful treatment (odds ratios, 3.1 and 1.8, respectively), as did those who were Rh-negative (5.6) and those who had never given birth (2.3). The overall success rate was 92% or higher among women who had had lower abdominal pain, were Rh-negative, or were nulliparous and had had vaginal bleeding.
In a second set of logistic regressions, the researchers examined factors associated with explusion after a single dose of misoprostol. The likelihood of this outcome was significantly elevated for women who had had vaginal bleeding within 24 hours before the procedure (odds ratio, 1.8) and for women who were nulliparous (2.0) or had given birth only once (1.8). Notably, type of pregnancy failure and gestational age at the time of treatment were not significantly related to either overall success or success after one dose.
The researchers remark that "because women generally prefer some treatment to no treatment, the success rate of vaginal misoprostol for early pregnancy failure appears to be an advance in medical treatment." At the same time, they note that the likelihood of success after one dose of misoprostol may be the most important factor for women deciding between medical treatment and vacuum aspiration. "Health care providers," they conclude, "should discuss the options for treatment of early pregnancy failure with a keen sense of what the patient strongly desires." —D. Hollander
1. Creinin MD et al., Factors related to successful misoprostol treatment for early pregnancy failure, Obstetrics & Gynecology, 2006, 107(4):901–907.