Physiological Changes in Pregnancy
During pregnancy fibrinogen (LQ)
|D||increases initially then falls|
a. Pregnancy itself is a factor of hypercoagulability (pregnancy-induced hypercoagulability), as a physiologically adaptive mechanism to prevent postpartum bleeding.
b. Pregnancy changes the plasma levels of many clotting factors, such as fibrinogen, which can rise up to three times its normal value. Thrombin levels increase. Protein S, an anticoagulant, decreases.
c. However, the other major anticoagulants, protein C and antithrombin III, remain constant. Fibrinolysis is impaired by an increase in plasminogen activator inhibitor-1 (PAI-1 or PAI) and plasminogen activator inhibitor-2 (PAI-2), the latter synthesized from the placenta.
d. Normal levels of Fibrinogen are 150-300 mg/dl. The rise is 100% and levels are elevated to 600 mg/dl. Hypofibrinogenemia is level less than 100mg/dl which is seen in IUD.