Methotrexate for Ectopic Pregnancy

Methotrexate (MTX)

Background

• Dihydrofolate reductase inhibitor
• Overall success rate for treating ectopic pregnancy = 71-94%
• Success rate of single-dose MTX for beta-hCG >5,000 mIU/mL = 85.7%

Side Effects

• Abdominal pain
• Nausea/vomiting
• Stomatitis

Eligibility / Contraindications for MTX in Ectopic Pregnancy

Eligibility Criteria: (Need to fulfill all criteria)

• High clinical suspicion or confirmed ectopic pregnancy
• Hemodynamically stable
• Unruptured mass
• Able to comply with close follow-up
• Normal creatinine, liver transaminases, WBC, hematocrit, and platelet counts

Contraindications:

• Breastfeeding
• Overt or lab evidence of immunodeficiency
• Alcoholism, alcoholic or chronic liver disease
• Preexisting blood dyscrasias or significant anemia
• Known sensitivity to MTX
• Active pulmonary disease
• Peptic ulcer disease
• Hepatic, renal, or hematologic dysfunction
• Gestational sac >3.5 cm on U/S (relative contraindication)
• Embryonic cardiac motion on U/S (relative contraindication)

Single-Dose Regimen

• Day 1: Methotrexate 50 mg/m2 IM

Follow up with obstetrician:

• Days 4 and 7: Measure beta-hCG
• Between Days 4 and 7: Check for 15% beta-hCG decrease
• Measure beta-hCG weekly until non-pregnant level
• If beta-hCG dose not decrease by >15% as expected, re-dose 50 mg/m2 IM and repeat B-hCG on days 4 and 7 after 2nd dose.

Alternative Regimens

• Two-Dose and Fixed Multidose regimens available as proposed by ACOG guidelines - Consider for beta-hCG level >5,000 mIU/mL

References

• ACOG Practice Bulletin No. 94:Medical management of ectopic pregnancy. Obstet Gynecology. 2008; 111(6):1479-85. [PubMed]