Day 1 change in maternal serum β-HCG levels as an early predictor of successful medical therapy in ectopic pregnancies

Objective: To evaluate the role of beta-HCG level changes between days 0 and 1 as an early predictor of methotrexate success in cases of tubal ectopic pregnancy. Methods: A retrospective study included 86 tubal ectopic pregnancies treated with a single-dose methotrexate protocol of 50 mg/m(2) of body surface. beta-HCG measurements were taken on days 0, 1, 4 and 7 where day 0 is the day of methotrexate injection. Day 0 beta-HCG and the percentage change in beta-HCG level between days 0 and 1 (HCG index) were calculated and compared between patients who were successfully or unsuccessfully treated. Receiver operator characteristics (ROC) curves were plotted to identify the best cutoff levels. Results: The average level of beta-HCG (1416.8 versus 2502.5 IU/L, p=.001) and its increment after 24 hours (12.9 versus 27.1%, p=.001) were significantly lower in the successful treatment group. ROC curves for beta-HCG level and its relative increment revealed that cutoff values of <= 1550 IU/L and <= 13% increment showed a sensitivity of 90 and 70% respectively for successful methotrexate treatment. Conclusion: Day 0 beta-HCG level <= 1550 IU/L and an increment of <= 13% after 24 hours are early predictors of successful methotrexate treatment for tubal ectopic pregnancy.