ACOG practice bulletin. Medical management of tubal pregnancy. Number 3, December 1998. Clinical management guidelines for obstetrician-gynecologists. American College of Obstetricians and Gynecologists

Ectopic pregnancy is a major health problem for women of reproductive age and, in the United States, is the leading cause of pregnancy-related death during the first trimester. Diagnosis and treatment of tubal pregnancy before tubal rupture occurs decreases the risk of death. Early detection may make it possible for some patients to receive medical therapy instead of surgery. Methotrexate, a folinic acid antagonist, has been used to treat patients with small unruptured tubal pregnancies. The purpose of this document is to present evidence, including risks and benefits, about methotrexate as an alternative treatment for selected ectopic pregnancies.

Published by International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics, 1999. The guideline itself is at the source linked here.

pubmed.ncbi.nlm.nih.gov/10390113/