Study on the presence of abnormal proteins in the serum of oral contraceptive users.
Beaumont reported that current and former oral contraceptive users and subjects with thromboembolic disease characteristically demonstrate elevated amounts of precipitated proteins, designated as "globulines anormalement precipitables (GAP)," following treatment of their sera with 25% saturated ammonium sulfate. In the present study, the reproducibility of Beaumont's methods and results was investigated in groups of women consisting of never users, current users, former users, and thrombosis subjects. The current users had the lowest serum GAP levels and no bimodal distribution. Values were higher for the never users and former users and highest in the thrombosis group. Race affected serum GAP values; mean values for blacks were significantly higher than for Caucasians. This study does not support Beaumont's earlier findings.