Is it necessary to check β-hCG levels on day 4 after single-dose methotrexate treatment of ectopic pregnancy? A retrospective cohort study

Aim: This study aimed to investigate the usefulness of the percentage change in serum β-hCG levels from days 1 to 7 for predicting treatment success in patients treated with a single dose of methotrexate for tubal ectopic pregnancy. Materials and Method: This retrospective observational study investigated 74 patients treated with a single-dose methotrexate regimen for tubal ectopic pregnancy at a tertiary hospital between January 2020 and December 2023. Patients were subdivided into two groups based on reduction in serum β-hCG levels between days 4 and 7: <15.0% - \\\"successful treatment\\\" or ≥15.0% - \\\"need a second dose methotrexate\\\". Then, the percentage change in serum β-hCG levels between days 1 and 7 and its usefulness in predicting \\\"successful treatment\\\" were analyzed. Results: Treatment was considered successful in 66 of the 74 patients (86.5%). There was a negative linear correlation between treatment success and percentage change in serum β-hCG levels from day 1 to day 7 (P<0.001). ROC curve analyses revealed that the sensitivity of treatment success prediction decreased with increasing percentage change in serum β-hCG levels from days 1 to 7. The sensitivity and specificity of the-25.0%, 0.0%, and +25.0% changes in serum β-hCG levels from day 1 to day 7 for predicting treatment success were 100.0%-41.0%, 90.0%-93.7%, and 80.0%-96.9%, respectively. Conclusion: Monitoring the percentage change in serum β-hCG levels from days 1 to 7 may effectively replace the traditional protocol, particularly when patient compliance is challenging or day 4 measurements are impractical.