The effect of oral contraceptive steroids on branches of the uterine artery.

Uteri from 38 patients exposed to oral contraceptive steroids and from 7 unexposed controls were examined for lesions in small branches of the uterine artery. Moderate or severe cellular proliferation of the intimal layer was found in 82% of patients exposed to exogenous steroids, but minimal or no involvement was found in the remaining 18% and in unexposed patients. The severity of involvement correlated with duration of exposure to contraceptive steroids but decreased in those patients who had stopped medication prior to surgery. This lesion has been reported previously in autopsy studies of women receiving contraceptive steroids and dying from vascular disease, but is now shown to be common in asymptomatic women receiving oral contraceptive pills.