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Updated: May 23, 2026

Comprehensive Evaluation of the Effectiveness and Safety of Placenta-Targeted Drug Delivery Using Three Complementary Methods
Published on: September 10, 2018
Methotrexate: the pharmacology behind medical treatment for ectopic pregnancy
1Department of Obstetrics & Gynecology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA. c-stika@northwestern.edu
Abstract:
Previously established as a chemotherapeutic agent for decades, methotrexate has been adapted for use as a medical therapy for unruptured ectopic pregnancies. Its mechanism of action, competitive inhibition of folate-dependent steps in nucleic acid synthesis, effectively kills the rapidly dividing ectopic trophoblast. However, the same action on normal cells is the basis for many of its adverse effects.
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