Thrombin inhibitors in women on oral contraceptives.

Progressive antithrombin activity and the immunological levels of antithrombin III, alpha 2-macroglobulin, and alpha 1-antitrypsin were measured in women at various intervals during treatment with oral contraceptives and in a group of untreated women. No significant changes were observed in any of the above parameters. In both control and treated women, there was a positive statistical correlation between progressive antithrombin activity and antithrombin III immunological levels, whereas no correlation was found between the former and alpha 1-antitrypsin or alpha 2-macroglobulin immunological levels. This study questions the possibility of thrombin inhibitors being selective signs of hypercoagulability during treatment with oral contraceptives.