Serum protein fractions. Effects of oral contraceptives and pregnancy.

As a part of a longitudinal study to determine the side effects of oral contraceptive drugs (OCs), protein electrophoresis studies were carried out on sera obtained from 4057 current users of OCs, 9774 nonusers, and 624 women in the first trimester of pregnancy. Albumin and gamma globulin levels were lower in OC users than in nonusers; alpha-1, alpha-2, and beta fractions were higher. A similar effect was observed during the first trimester of pregnancy. The changes were temporary and reverted to normal within 12 weeks of OC withdrawal. The dosage of the estrogenic component appeared to be directly related to the lower concentration of albumin in users. The mechanisms of these changes were not well identified but very likely represent a direct effect on the metabolism of proteins.