Fibrin 2-4 g/L and no more than 6 g/L is normal in late pregnancy. After pregnancy, the blood is in a hypercoagulable state, which makes most of the coagulation factors increase to prepare for the prevention of perinatal hemorrhage. In late pregnancy, the prothrombin time and activated partial thromboplastin time is mildly shortened, the coagulation time is not significantly changed, the amount of fibrinogen will be increased or decreased by 50% compared with the pre-pregnancy, 2-4g/L in late pregnancy, not more than 6g/L is normal. As the venous blood threshold of non-pregnant women during pregnancy, and different degrees of damage to the vessel wall can lead to hypercoagulable blood during pregnancy, and increase the risk of thrombophilia in pregnant women, so after delivery or cesarean section can be carried out under the guidance of the doctor to moderate activity, which is conducive to the recovery of the body, but also can reduce the risk of thrombophilia.