Deep vein thrombosis (DVT) is serious condition which is reponsible for deaths from pulmonary embolism or debilitating complications from postthrombotic syndrome, and the incidence is not infrequent from hypercoagulability in some gynecologic and obstetric settings. In high-risk patients with clinical symptoms of edema or pain of lower extremity, careful consideration should be paid to exclude DVT. Because clinical examination alone has a sensitivity of only 30% in diagnosing DVT, clinicians should have a low threshold to order diagnostic tests. Duplex ultrasonography is the most useful non-invasive
test for detecting acute DVT, and highly sensitive and specific.