Attempted Abortion with Aminopterin (4-Amino-Pteroylglutamic Acid)

Pteroylglutamic acid (PGA, folic acid) plays an important role in many biological reactions, and PGA deficiency may lead to death of mammalian embryos. Nelson and Evans¹demonstrated reproductive failure in rats kept on a PGA-deficient diet containing succinylsulfathiazole and a crude PGA antagonist. Thiersch and Philips²induced fetal death in rodents kept on an adequate diet by administration of aminopterin (4-amino-pteroylglutamic acid), a powerful PGA antagonist. Later Giroud and Lefebvres-Boisselot³and Nelson, Asling, and Evans⁴produced multiple congenital abnormalities by maternal PGA deficiencies during gestation. Aminopterin has also been used to induce therapeutic abortions in women with tuberculosis or cancer. In 10 out of 12 cases reported by Thiersch⁵oral doses of 6 to 12 mg. aminopterin induced fetal death in the first trimester of pregnancy, followed by spontaneous delivery of the products of conception. The doses lethal to the embryo had only mild effects