Predictors of treatment failure for ectopic pregnancy treated with single-dose methotrexate

Abstract 

Objective: To determine variables that predict treatment failure after methotrexate (MTX) treatment of ectopic pregnancy.

Design: Retrospective cohort study.

Setting: Canadian teaching hospital.

Patient(s): Sixty patients diagnosed with and treated for ectopic pregnancy.

Intervention(s): A single dose of methotrexate (50 mg/m²) by i.m. injection.

Main Outcome Measure(s): Resolution of serum β-hCG or clinical evidence of treatment failure.

Result(s): Treatment failure was observed following methotrexate administration in 65% of cases when initial β-hCG was >4000 IU/L, but in only 7.5% of patients when serum β-hCG was <4000 IU/L (OR = 52.06, 95% CI 4.88–555.56). Patients who presented with pelvic pain without tenderness had treatment failure 56% of the time versus only 17% in those without pain (OR = 9.20, 95% CI 1.02–82.60). Treatment failure also occurred in 53% of patients presenting with vaginal bleeding versus 16% without bleeding (OR = 6.18, 95% CI 0.73–51.93).

Conclusion(s): Methotrexate should not be used to treat ectopic pregnancy when initial β-hCG is >4000 IU/L. Caution should also be exercised in using methotrexate for ectopic pregnancy when the patient presents with bleeding or pain even without tenderness.

Keywords:  Ectopic pregnancy, methotrexate, treatment predictors