Human chorionic gonadotropin patterns after a single dose of methotrexate for ectopic pregnancy.

Objective: The great variability in human chorionic gonadotropin (HCG) levels after a single dose of methotrexate (MTX) for ectopic pregnancy makes it difficult to predict treatment failure. We describe different patterns of HCG levels.

Study Design: Fifty patients were injected i.m. with 50mg/m(2) of MTX for an ectopic pregnancy. Venous blood samples for HCG detection were obtained on the day of treatment (day 0), day 3 and day 7 and weekly until values were undetectable. Patients were classified as: group 1, persistent pathology (n=11); group 2, complete resolution with a decrease of HCG levels at day 3 (n=30); group 3, complete resolution after a rise of HCG values at day 3 (n=9). Statistical analysis was performed using the Mann-Whitney non-parametric test with 95% confidence intervals.

Results: Values of day 0 were similar for all the groups. HCG levels of group 3 decreased rapidly after day 3 and at day 7 they were significantly different from levels of group 1. Differences in HCG levels between groups 2 and 3 became indistinguishable from day 21.

Conclusion: The observation of patients undergoing resolution after an initial increase of HCG levels justify an expectant management for 1 week in clinically stable patients. The strategy to separate HCG curves in patients undergoing resolution may shed light on the different clinical responses to therapy for ectopic pregnancies. However, the phenomenon of the immediate rise of HCG should be better investigated.