Predictors of failure of the commonly used single-dose methotrexate protocol for treating tubal ectopic pregnancies.

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 β-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 = 92); Group 2 (n = 28). β-hCG levels measured at all time points, and day (0-4) and day (4-7) changes, presence of adnexial masses, and infertility were significantly different among the two groups. Only the day (0-4) and day (4-7) changes in β-hCG levels were independent predictors of failure.

Conclusion: Day (0-4) thresholds or newly defined day (4-7) thresholds were not more sensitive than the conventional day (4-7) criteria. Day (0-4) β-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 (4-7) criteria. In contrast, no cases of treatment failure were observed if the day (0-4) decrease was >26.6%.