Absence of antisteroid antibodies in oral contraceptive users presenting with vascular events.

Previous reports speculated that vascular events could be related to the development of antibodies against synthetic steroids contained in oral contraceptives or other hormonal treatments. This study describes original immunoassays designed to detect antisynthetic steroid antibodies. In a first step, the assays were characterized and validated using animal-raised antisteroid antibodies. In a second step, a population of 88 oral contraceptive users, 47 of them having developed a vascular thrombosis during synthetic steroid use and 41 serving as healthy control users, were tested. Detection of antibodies against ethinylestradiol, levonorgestrel, norethisterone, cyproterone acetate, and gestodene showed that the values obtained in normal oral contraceptive users as well as thrombosis patients are very low, and show no statistically significant difference between the two groups tested. Taken together, these data indicate that the "immunological hypothesis" related to antisteroid antibodies is unlikely to explain the pathogenesis of vascular events in oral contraceptive users.