Candidates for Methotrexate Medical management of ectopic pregnancies with methotrexate is safe and effective, however, not all patients are candidates for this medical therapy. According to American College of Obstetricians and Gynecologists (ACOG) guidelines, methotrexate therapy can be considered for those patients with confirmed, or high suspicion for, ectopic pregnancy who are hemodynamically stable with no evidence of rupture. Table 20.2 documents the absolute contraindications to methotrexate therapy including breastfeeding, hepatic, renal, or hematologic disorders and known sensitivity to methotrexate. A patient who is unable to comply with the follow-up protocol should not be offered medical management. Relative contraindications to methotrexate therapy include gestational sac greater than or equal to 3.5 cm and embryonic cardiac motion (Table 20.2). Prior to the administration of methotrexate, a patient should have a complete blood count, blood type, liver function tests, electrolyte panel including creatinine, and a chest x-ray if there is any history of pulmonary disease. These studies are usually repeated 1 week after administration of methotrexate to evaluate for any potential complications from the therapy (190).
Methotrexate Dosing Regimens Methotrexate is usually given via intramuscular injection but can be administered orally or by intravenous infusion. Methotrexate traditionally was administered using a multidose regimen, but single dosing protocols were developed that are easier for patient compliance (194).
Table 20.3 Methotrexate Treatment Regimens
Administer MTX 1 mg/kg IM days 1, 3, 5, 7
Administer leucovorin 0.1 mg/kg days 2, 4, 6, 8
Measure β-hCG levels on days 1, 3, 5, 7 until 15% decrease between two measurements.
Once β-hCG levels drop 15%, stop MTX and monitor β-hCG weekly until nonpregnant level
If levels drop by 15%, monitor β-hCG weekly until nonpregnant level
If levels do not drop by 15%, repeat dose of MTX and measure β-hCG on days 4 and 7
If levels drop by 15%, monitor β-hCG weekly until nonpregnant level
If levels do not drop by 15%, repeat dose of MTX on days 7 and 11 and measure β-hCG on days 7 and 11. If levels drop 15%, monitor β-hCG weekly until nonpregnant level
MTX, methotrexate; IM, intramuscular; β-hCG, β-human chorionic gonadotropin; Adapted from ACOG Practice Bulletin Medical Management of Ectopic Pregnancy, 2008.