Presence of the "Beaumont" protein in serum of oral contraceptive users.

The level of the "Beaumont" protein present in serum was measured by a population of 223 black and 76 Caucasian women with different exposures to oral contraceptives (OCs). No differences were found in the values in nonusers, past users, current users, or new users of OCs. The values were higher in black nonusers and users than in comparable Caucasian groups, suggesting a racial difference. A group of 55 thrombotic women were subclassified by type of thrombosis and exposure to OC therapy. No significant difference was seen between the values in thrombotic women exposed or not exposed to OCs. A similar result was obtained when the types of thrombosis (arterial or venous) were compared. These results do not confirm Beaumont's hypothesis that antibodies are induced by contraceptive steroids in a subgroup of women on OC therapy.