The optimal cutoff serum level of human chorionic gonadotropin for efficacy of methotrexate treatment in women with extrauterine pregnancy

Abstract

Objective: To evaluate the efficacy of methotrexate treatment for extrauterine pregnancy and define criteria for prediction of success.

Methods: Of 829 patients with an ectopic pregnancy admitted to E. Wolfson Medical Center, Holon, Israel, from January 1997 through December 2009, 238 had asymptomatic tubal pregnancies and increasing serum β-human chorionic gonadotropin (βhCG) levels. These patients were treated with a single intramuscular injection of 50mg of methotrexate (MTX) per square meter of body surface. Success was defined as undetectable βhCG levels without the need for a surgical intervention.

Results: The groups of patients successfully treated (n=167 [70%]) and unsuccessfully treated (n=71 [30%]) were compared. They were similar regarding age and gravidity. The initial serum βhCG level was significantly higher in the latter group than in the former (3798 mIU/mL vs. 1601 mIU/mL, P<0.01). The success rate was 88% when initial βhCG levels were less than 1000 mIU/mL, 71% when they were between 1000 and 2000 mIU/mL, and only 59% when they were between 2000 and 3000 mIU/mL.

Conclusion: Methotrexate treatment is a safe and effective alternative to surgery. However, patients with initial βhCG levels higher than 2000 mIU/mL should only be offered the surgical approach.