Single dose methotrexate for treatment of ectopic pregnancy: risk factors for treatment failure

Objective: To identify risk factors for single dose methotrexate (MTX) failure among patients treated for ectopicpregnancies.Design: Retrospective cohort.Materials and methods: Seventy women diagnosed with an ectopic gestation treated with MTX. After a single dose,66 (94.3%) patients experienced ectopic resolution, three (4.3%) patients needed a second dose of MTX, and one(1.4%) patient had a subsequent tubal rupture.Main outcome measure(s): Predictive variables for failure of single dose MTX, including human chorionicgonadotropin (hCG) value, fetal sac size, patient age, parity and history of previous miscarriages.Result(s): Ectopic pregnancies that failed to resolve following a single dose MTX were associated with increasedmaternal age, history of spontaneous abortions, larger sac sizes ( 3.4 cm), and higher â-HCG levels ( 2000mIU/mL). Multiple regression analysis demonstrated that the size of the embryonic sac was the most important variable in failures of single dose methotrexate treatment.Conclusion: Size of gestational sac and the pre-treatment level of HCG should be considered as independent risk factors for treatment failure of single dose methotrexate treatment.