Hemostasis in Pregnant Saudi Women

Abstract

A cross-sectional study of various hemostatic variables was undertaken in women during the three trimesters of normal pregnancy. In the third trimester of pregnancy, there was significant elevation of plasma fibrinogen, 55%; factor VIII activities, 64%; factor VIII:ristocetin cofactor, 44% ; factor VIII-related antigen, 49% ; factor X, 9% ; and plasminogen, 19%, and a reduction of antithrombin III, 10%; alpha2-antiplasmin, 7%; and platelet count, 20%, compared with those values obtained in healthy nonpregnant controls. These fluctuations developed gradually during the first and second trimesters. Prothrombin time, partial thromboplastin time, thrombin time, and reptilase time were similar in pregnant women and nonpregnant controls. Platelet aggregation in response to adenosine diphosphate, collagen, adrenaline, and arachidonic acid was significantly reduced in pregnant women compared to controls. The reduced platelet aggregability in Saudi pregnant women may counterbalance the increased plasmatic coagulation potential, thereby minimizing the risk of thromboembolic disease during pregnancy.