Single dose methotrexate therapy: application to interstitial ectopic pregnancy.

A woman with a small (6-mm gestational sac) interstitial pregnancy had complete resolution after medical therapy alone. A single cycle of methotrexate 50 mg/m2 was used as outpatient treatment without any operative procedure either for diagnosis or intervention. The guidelines that have evolved for selection of women for single dose methotrexate treatment for both intrauterine and tubal ectopic pregnancies may be applicable to interstitial ectopic pregnancy as well. A suggested framework for treatment decisions is presented.