Hemostasis in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies

Our purpose was to determine the hemostatic changes in the uteroplacental and peripheral circulations in normotensive and pre-eclamptic pregnancies.

This prospective, observational study involved 2 patient groups. Group 1 consisted of 30 normotensive women and 22 women with pre-eclampsia who were followed up longitudinally through pregnancy and post partum. Group 2 consisted of 20 women with established pre-eclampsia and 19 normotensive control subjects, all undergoing cesarean section. Plasma levels of thrombin-antithrombin III complex, soluble fibrin, plasmin-alpha2-antiplasmin complex, and fibrin-degradation product (D-dimer) were measured in blood drawn from the antecubital vein (group 1) and from both the antecubital and uterine veins (group 2). Data were analyzed by analysis of variance.

In group 1 levels of thrombin-antithrombin III complex, soluble fibrin, and fibrin-degradation product were significantly higher during normal pregnancy than at 6 weeks post partum. Plasmin-alpha2-antiplasmin complex levels did not change. No differences between the pre-eclamptic and normotensive pregnancy groups were found for any of the hemostatic markers. In group 2 normotensive women undergoing cesarean section, thrombin-antithrombin III complex and soluble fibrin levels were significantly higher in the uterine vein than in the antecubital vein. In group 2 women with pre-eclampsia, thrombin-antithrombin III complex and fibrin-degradation product levels were significantly higher in the uterine vein than in the antecubital vein. In addition, plasmin-alpha2-antiplasmin complex and fibrin-degradation product levels were higher and soluble fibrin levels were lower in the uterine vein in the pre-eclamptic group than in the normotensive group.

Both the coagulation and fibrinolytic systems are activated during normal pregnancy. Activation of these systems is more marked in the uteroplacental circulation than in the systemic circulation in both normotensive and pre-eclamptic pregnancies. An abnormal pattern of hemostasis occurs in the uteroplacental circulation in pre-eclampsia.