Methotrexate (50 mg/m2 intramuscularly and 50 mg orally) followed by vaginal misoprostol have proven to be > 90% effective at causing abortion in women at less than 49 days’gestation. Although the effectiveness of the oral dose (which has a lower serum bioavaiIability) demonstrates that a methotrexate dose of 50 mglm’may be more than necessary, an intramuscular regimen is more advantageous because it is less costly. This trial was designed to investigate the potential effectiveness of a single dose of methotrexate, 75 mg intramuscularly, in a regimen for early abortion. One hundred subjects received 75 mg methotrexate intramuscularly followed 5 to 6 days later by 800 pg misoprostol vaginally. The misoprostol dose was repeated if the abortion did not occur. Outcome measures included successful abortion (complete abortion without requiring a surgical proce- dure), duration of vaginal bleeding, and side effects. One subject was lost to Jollow-up. Complete abortion ...