OBJECTIVE: Medical abortion regimens have become more widely used to terminate early pregnancies. Medical abortion providers are concerned to diagnose and exclude women with ectopic pregnancy before initiating treatment, as with any early pregnancy termination. Yet, there is little information about whether the various pretreatment screening methods used are adequate. We reviewed published literature to determine the overall success of screening for ectopic pregnancy before medical abortion treatment. DATA SOURCES: We searched MEDLINE for articles on medical abortion regimens published before July 2003. METHODS OF STUDY SELECTION: We selected English language articles of studies of medical abortion with sample sizes greater than 100, which reported on ectopic pregnancy diagnosed after medical abortion treatment. Fifty-seven of 85 prospective studies and randomized trials (69%) met these inclusion criteria. We also included data from 2 unpublished studies because they were large and well-controlled and because they included serious adverse events known to us, which we did not deem fair to exclude from our analysis. TABULATION, INTEGRATION, AND RESULTS: Each article was reviewed by one author. Data from selected studies were compiled, and the frequency of ectopic pregnancy diagnosed after medical abortion treatment was calculated. Ectopic pregnancy was diagnosed very infrequently following medical abortion procedures, occurring in only 10 of 44,789 (0.02%) women. CONCLUSION: The very low frequency of ectopic pregnancies diagnosed after medical abortion treatment demonstrates that the various pretreatment screening methods that providers use to exclude patients with ectopic pregnancies are successful. Further, there is no evidence to suggest that medical abortion treatment leads to unusual complications for women with ectopic pregnancies.