The incidence rate of DVT is about 10% to 40% in medical or general surgical patients without prophylaxis .With prophylaxis, the postoperative incidence of VTE was 1.14% in women with gynecological disease, and 0.7% in patients undergoing laparoscopic gynecological surgery, 0.3% in patients undergoing urogynecological surgery, and 4% in gynecological cancer patients, respectively. Most of published studies enrolled only symptomatic patients with DVT, whereas asymptomatic patients could be easily neglected under the absence of effective detection. In fact, approximately 50% of DVT patients are silent, so the actual incidence of postoperative DVT might be higher than reported . The asymptomatic DVT has been confirmed to increase the development of post-thrombotic syndrome (PTS).