Trends in serum human chorionic gonadotropin levels 0-4 days after methotrexate administration for predicting tubal ectopic pregnancy treatment success.

OBJECTIVE

To evaluate serum human chorionic gonadotropin (HCG) levels 0-4 days after single-dose methotrexate administration for tubal ectopic pregnancy.

METHODS

The present retrospective study included women with tubal ectopic pregnancy treated by methotrexate at a tertiary hospital in Hong Kong, China, between January 1, 2007, and December 31, 2016. Patients were stratified serum HCG levels rose or fell from day 0-4 post-administration. Trends in day 0-4 serum HCG to predict treatment success were compared with that of day 4-7 serum HCG. The optimal drop in HCG was identified by receiver operating characteristic curve analysis.

RESULTS

There were 102 patients included. The positive predictive value (PPV) of day 0-4 serum HCG for treatment success was 91% (95% confidence interval [CI] 82-96), which is comparable to the current criterion of a 15% drop in day 4-7 serum HCG (PPV 91%, 95% CI 84-95). A 6% drop in day 0-4 serum HCG was the best predictor of treatment success (PPV 96%, 95% CI 86-99).

CONCLUSION

A drop in day 0-4 serum HCG provided earlier prognostic information and was not inferior to the current criterion.