Objectives: This study identified patients who would benefit from an earlier additional medical intervention and/or continuing close surveillance even if commonly used parameters indicated sufficient medical treatment to determine markers of treatment failure. Materials and methods: A retrospective analysis of patients with a preliminary diagnosis of ectopic pregnancy treated with the single-dose methotrexate protocol. Group 1: cases cured with a single dose of methotrexate; Group 2: cases who required more than one dose of methotrexate or surgery following the first dose. Demographics, clinical/sonographic findings, observation period, and b-human chorionic gonadotropin (hCG) levels were compared among the two groups. Thresholds were defined and a regression analysis was performed to define independent predictors of failure. Results: Data from 120 patients were analyzed: Group 1 (n ¼ 92); Group 2 (n ¼ 28). b-hCG levels measured at all time points, and day (0e4) and day (4e7) changes, presence of adnexial masses, and infertility were significantly different among the two groups. Only the day (0e4) and day (4e7) changes in b-hCG levels were independent predictors of failure. Conclusion: Day (0e4) thresholds or newly defined day (4e7) thresholds were not more sensitive than the conventional day (4e7) criteria. Day (0e4) b-hCG levels increased by more than 9.7% in half the patients who required additional methotrexate doses or surgery despite fulfillment of the conventional day (4e7) criteria. In contrast, no cases of treatment failure were observed if the day (0e4) decrease was >26.6%.
