Haemostasis and coagulation in pregnancy

Pregnancy is a hypercoagulable state.
Almost all procoagulant factors, including factors VII, VIII, IX, X, XII, and fibrinogen, are increased.
Fibrinogen is increased by 50% (from 300mg/dL to 450mg/dL).
Von Willebrand factor also increased.
Protein S activity decreases.
Activated protein C resistence increased.
Antithrombin III levels remain  unchanged.
Plasma homocystiene concentration are lower in normal pregnancies.
Maternal plasma D dimer concentration increases progressively from conception until delivery.
Incidence of venous thromboembolic complications is five time greater during pregnancy.