Diagnosis of deep venous thrombosis and pulmonary embolism in pregnancy.

Accurate diagnosis of deep venous thrombosis and pulmonary embolism is required because treatment can be lifesaving, although inappropriate anticoagulation exposes the mother and fetus to hemorrhage and other hazards. Clinicians must be aware of which patients are at risk, as deep venous thrombosis is frequently asymptomatic. Clinical diagnosis is unreliable for deep venous thrombosis and pulmonary thromboembolism; therefore, objective tests are required. Venography is the gold standard test for deep venous thrombosis but is invasive. It has been superseded by less invasive tests such as compression ultrasound. This test, although not yet rigorously scrutinized in pregnancy, is now the first-line investigation. Where doubt remains, venography, CT, and magnetic resonance imaging have a role. Ventilation-perfusion scanning is the pivotal test for pulmonary thromboembolism for pregnancy, and it need not expose the fetus to excess radiation. If the results of this test are unclear, deep venous ultrasound can guide management of suspected pulmonary thromboembolism, thus avoiding pulmonary angiography.