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

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%.