Management of venous thromboembolism during pregnancy

The incidence of venous thromboembolism (VTE) probably increases 2-4-fold in pregnancy and is higher after a caesarean section than after vaginal delivery. Management of VTE in pregnancy is challenging. Many diagnostic tests are less accurate in pregnant than in non-pregnant patients and some radiologic procedures expose the fetus to ionizing radiation, although this can be reduced by taking appropriate precautions. Compression ultrasonography (CUS) is the test of choice for deep vein thrombosis (DVT), whereas for PE, V/Q lung scan is the first-line test, followed by CUS if the results are non-diagnostic. Anticoagulants that have been evaluated for the prevention and treatment of VTE in pregnancy include heparin and heparin compounds, and coumarin derivatives. When determining the optimal treatment regimens, it is important to consider: (i) the safety of the drug for the fetus and mother; (ii) the efficacy of the regimen; and (iii) the dose regimens for acute and secondary treatment, and during delivery and postpartum. Heparins are safer than coumarins for the fetus, as they do not cross the placental barrier. Heparins, particularly unfractionated heparin (UFH) and low molecular weight heparin (LMWH) tend also to be safer for the mother than other compounds. Of the two, LMWHs, although more expensive, are associated with lower rates of bleeding complications, and heparin-induced thrombocytopenia and osteoporosis, than UFH, and should therefore be the treatment of choice in VTE during pregnancy. Patients with prior VTE or a hypercoagulable state have an increased risk of VTE during pregnancy. Depending on the presence of one or both of these factors, clinical surveillance, with anticoagulant treatment where necessary, is recommended.