Thrombosis in pregnancy

Pregnancy and the postpartum period are critical clinical periods notorious for the induction of hypercoagulable states. These conditions fulfill the Virchow triad: (1) increase in procoagulant factors and decrease in anticoagulants, (2) stasis that is caused by mechanical factors related to the gravid uterus and from compression of the left iliac vein by the right iliac artery, and (3) endothelial injury during delivery. Consequently, thrombotic events are the leading cause of morbidity and mortality during pregnancy. Hereditary and acquired thrombophilia add to thrombotic risk in pregnancy, with antiphospholipid syndrome being the most recognized cause. In suspected cases of deep vein thrombosis (DVT) the precise diagnosis is made by compression duplex ultrasonography, while in patients with suspected pulmonary embolism (PE), ventilation perfusion scan or computed tomographic angiography are the diagnostic imaging of choice. Nevertheless, the accurate diagnosis of both DVT and PE remains a difficult challenge in pregnancy and a high level of clinical suspicion is warranted to avoid missing these critical diagnoses. The prevention and treatment of venous thromboembolism in pregnancy are based on administration of low-molecular-weight heparin. Notably, the activation of the hemostatic system in placental blood vessels may lead to gestational vascular complications.