In the US, thromboembolic disorders—deep venous thrombosis Deep Venous Thrombosis (DVT) Deep venous thrombosis (DVT) is clotting of blood in a deep vein of an extremity (usually calf or thigh) or the pelvis. DVT is the primary cause of pulmonary embolism. DVT results from conditions... read more (DVT) or pulmonary embolism Pulmonary Embolism (PE) Pulmonary embolism (PE) is the occlusion of pulmonary arteries by thrombi that originate elsewhere, typically in the large veins of the legs or pelvis. Risk factors for pulmonary embolism are... read more (PE)—are a leading cause of maternal mortality.
During pregnancy, risk is increased because
However, most thromboemboli develop postpartum and result from vascular trauma during delivery. The risk of developing a thromboembolic disorder Thromboembolic Disorders in Pregnancy In the US, thromboembolic disorders—deep venous thrombosis (DVT) or pulmonary embolism (PE)—are a leading cause of maternal mortality. During pregnancy, risk is increased because Venous capacitance... read more may be increased for about 6 weeks after delivery. Cesarean delivery also increases risk.
Symptoms of thrombophlebitis or their absence does not accurately predict the diagnosis, disease severity, or risk of embolization. Thromboembolic disorders can occur without symptoms, with only minimal symptoms, or with significant symptoms. Also, calf edema, cramping, and tenderness, which may occur normally during pregnancy, may simulate Homans sign.
Diagnosis of DVT is usually by Doppler ultrasonography. In the postpartum period, if Doppler ultrasonography and plethysmography are normal but iliac, ovarian, or other pelvic venous thrombosis is suspected, CT with contrast is used.
Diagnosis of PE is increasingly being made by helical CT rather than ventilation-perfusion scanning because CT involves less radiation and is equally sensitive. If the diagnosis of PE is uncertain, pulmonary angiography is required.
If DVT or PE is detected during pregnancy, the anticoagulant of choice is a low molecular weight heparin (LMWH). LMWH, because of its molecular size, does not cross the placenta. It does not cause maternal osteoporosis and may be less likely to cause thrombocytopenia, which can result from prolonged (≥ 6 months) use of unfractionated heparin. Warfarin crosses the placenta and may cause fetal abnormalities or death (see table Some Drugs With Adverse Effects During Pregnancy Some Drugs With Adverse Effects During Pregnancy Drugs are used in over half of all pregnancies, and prevalence of use is increasing. The most commonly used drugs include antiemetics, antacids, antihistamines, analgesics, antimicrobials, diuretics... read more ).
Indications for thrombolysis during pregnancy are the same as for patients who are not pregnant.
If PE recurs despite effective anticoagulation, surgery, usually placement of an inferior vena cava filter just distal to the renal vessels, is indicated.
If women developed DVT or PE during a previous pregnancy or have an underlying thrombophilic disorder, they are treated with prophylactic LMWH (eg, enoxaparin 40 mg subcutaneously once a day) beginning when pregnancy is first diagnosed and continuing until 6 weeks postpartum.
During pregnancy, risk of thromboembolic disorders is increased, but most thromboemboli develop postpartum and result from vascular trauma during delivery.
Symptoms of thrombophlebitis or their absence does not accurately predict the diagnosis, disease severity, or risk of embolization.
Diagnose deep vein thrombosis using Doppler ultrasonography, but postpartum, if Doppler ultrasonography and plethysmography findings are normal but pelvic venous thrombosis is suspected, do CT with contrast.
Diagnose pulmonary embolism using helical CT or, if needed, pulmonary angiography.
Low molecular weight heparin (LMWH) is the treatment of choice; warfarin should be avoided during pregnancy.
Treat high-risk women prophylactically with LMWH as soon as pregnancy is diagnosed and continue until 6 weeks postpartum.