Evaluation of the prethrombotic state in pregnancy and in women using oral contraceptives.

The purpose of this study was to determine the effects of pregnancy and oral contraceptive use on in vivo coagulation by measurement of plasma levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex. Fifty-four women with uncomplicated singleton gestations, 34 women using oral contraceptives and 45 non-pregnant controls were the subjects of this study. Levels of prothrombin fragment 1 + 2 and thrombin-antithrombin III complex were measured using enzyme linked immunoassays. In uncomplicated pregnancies, levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex increased significantly with advancing gestational age. Women using oral contraceptives had significantly higher levels of prothrombin fragment 1 + 2 and thrombin antithrombin III complex compared to non-pregnant controls. The significant increase in levels of prothrombin fragment 1 + 2 and thrombin-antithrombin III complex throughout gestation and in women using oral contraceptives provided evidence of thrombin activation during these clinical conditions.