Methotrexate and Fallopian Tubes in Ectopic Pregnancy

The condition of ectopic pregnancy is presented from different points of view, bringing out physiological explanations for its occurrence in primates and the striking absence in other mammals. Ectopic pregnancies have been described in several animal species such as cats, sheep, cows, horses, gerenuks, pigs, hamsters, rats, rabbits, marmosets, baboons, squirrel monkeys, owl monkeys and rhesus macaque. Methotrexate (MTX) has anticancer, antibacterial, antifungal, antiparasitic, immunosuppressive, antimitotic, embryotoxic and teratogenic effects. Methotrexate has species-specific effects. The purpose of this study was to investigate the medical treatment outcome of ectopic pregnancy by local administration of methotrexate and the adverse effects of increasing levels of MTX on the epithelium of the Fallopian tube as viewed by light microscopy. We treated patients with local and systemic regimen of methotrexate. Local applications were performed by direct injection of 0,5 mg/kg or 1 mg/kg methotrexate into the amniotic sac under sonographic control. Fallopian tubes were removed in patients with methotrexate treatment failure. The histological features we observed in the Fallopian tube were similar in all groups. In particular, histological findings showed necrosis and inflammatory infiltrate that was not quantitatively parallel to the increase in MTX dose. Fallopian tubes in human pregnancy could be resistant to the influence of MTX.