Thrombin inhibitors in women on oral contraceptives

Abstract

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.

PIP: Clinical research was conducted into the progressive antithrombin activity of plasma and the concentrations of AT-3(antithrombin-3), alpha2-M(alpha2-macroglobulin), and alphal-AT(alphal-antitrypsin) of women taking OCs (oral contraceptives). Women at various intervals during low-dose OC therapy were tested and compared with women not taking OCs. No significant changes were observed in any of these 3 parameters. In both groups of women the progressive antithrombin activity of plasma decreased gradually during the menstrual cycle, with the low at day 21. In both groups, there was a positive correlation between progressive antithrombin activity and antithrombin-3 immunological levels, but no correlation was found between the former and either of the other 2 factors. Findings from this study do not support previous reports that OC treatment lowers AT-3 levels. AT-3 cannot be considered a selective sign of hyper-coagulability during OC treatment.