Factors Related to Successful Misoprostol Treatment for Early Pregnancy Failure*

OBJECTIVE: To identify potential predictors for treatment success in medical management with misoprostol for early pregnancy failure. METHODS: We conducted a planned secondary analysis of data from a multicenter trial that compared medical and surgical management of early pregnancy failure. Medical management consisted of misoprostol 800 μg vaginally on study day 1, with a repeat dose if indicated on day 3. Women returned on days 3 and 15, and a telephone interview was conducted on day 30. Failure was defined as suction aspiration for any reason within 30 days. Demographic, historical, and outcome variables were included in univariable analyses of success. Multivariable analyses were conducted using clinical site, gestational age, and variables for which the univariable analysis resulted in a P < .1 to determine predictors of overall treatment success and first-dose success. RESULTS: Of the 491 women who received misoprostol, 485 met the criteria for this secondary analysis. Lower abdominal pain or vaginal bleeding within the last 24 hours, Rh-negative blood type, and nulliparity were predictive of overall success. However, only vaginal bleeding within the last 24 hours and parity of 0 or 1 were predictive of first-dose success. Overall success exceeds 92% in women who have localized abdominal pain within the last 24 hours, Rh-negative blood type, or the combination of vaginal bleeding in the past 24 hours and nulliparity. CONCLUSION: Misoprostol treatment for early pregnancy failure is highly successful in select women, primarily those with active bleeding and nulliparity. Clinicians and patients should be aware of these differences when considering misoprostol treatment. LEVEL OF EVIDENCE: II-2