Haemostasis and oral contraceptives.

Selected hemostasis parameters were assayed in 131 women ingesting different kinds of oral contraceptives and 36 control women. No differences were noted in the plasma levels of fibrinogen, antithrombin III, prekallikrein, alpha 2 antiplasmin, fibrinopeptide A, platelet factor 4 and beta-thromboglobulin. Protein C and plasminogen levels were significantly higher in pill users (p less than 0.001, p less than 0.01) and fibronectin levels were lower (p less than 0.05). Canonical correlation, performed between clinical parameters and hemostasis data, revealed a negative correlation between antithrombin III levels and family history for thromboembolic diseases. A positive correlation was noted between fibrinogen and fibronectin levels in obese OC users. The data suggest that women taking OCs are not in a state of "hypercoagulability."