Venous thromboembolism and pregnancy

VTE is a disease which is characterized by thrombus formation in the venous circulatory system. It affects mostly the veins of the lower extremities - deep vein thrombosis, and lungs - pulmonary embolism.

Pregnancy is a condition of the female body, which predispose to thrombotic events. The incidence of venous thromboembolism in pregnant women is 4-5 times higher than rates in the non-pregnant. The reason for this is the presence in the mother of the three leading factors called triad of Virchow, for thrombus formation: venous stasis, injury to the vascular wall and hypercoagulable. Hypercoagulable physiologically amendment normal pregnancy. In puerperium - the time from birth to eight weeks after, laboratory measures of clotting gradually normalize.

What are the risk factors for thrombotic event during pregnancy?

Proven have multiple risk factors - inherited or acquired for development of thromboembolism during pregnancy. The most common are hereditary factors - mutations in genes associated with encoding proteins involved in the coagulation system (inherited thrombophilias) - mutation of the factor V Leiden, mutation of prothrombin gene G20210A, deficiency of antithrombin III, impaired activation of plasminogen and others.

Acquired risk factors include obesity, lack of exercise a pregnant woman for more than four days, injuries, estrogen therapy, varicose veins flights lasting more than five hours. It was found that in pregnant women aged over 35 years the incidence of thrombotic events significantly appears against pregnant under age. Also, patients undergoing assisted reproductive technologies are at increased risk of deep venous thrombosis of the upper limbs due to the activation of the coagulation system by high levels of serum estrogens.

The highest risk of thrombotic event there in the third trimester of pregnancy and during the first week after birth. Venous stasis - a condition for forming a thrombus may occur in the first trimester, but the peak is 36 weeks This is due to the hormone progesterone-induced vasodilation and compression of the pelvic veins of the pregnant uterus.

The most frequently used anticoagulant is heparin. It is not toxic to the fetus, since it does not cross the placenta. Disadvantages of this treatment with the medicament is parenteral administration, and induced thrombocytopenia thereof over time (reduced platelet count). For these reasons during pregnancy treatment is performed with low molecular weight heparins, dosed subcutaneously twice daily during the day. They have a good performance against thrombophilic safe and have been proven less frequent bleeding episodes.