Objective  To discuss the clinical features, diagnosis, and treatment of deep venous thrombosis at specific positions in first trimester of pregnancy.

  Methods  Three cases in first trimester of pregnancy with deep venous thrombosis at specific positions treated in Peking Union Medical College Hospital in the period from September 2013 to June 2014 were retrospectively analyzed. The clinical manifestations, diagnosis, treatment, and prognosis of these cases were summarized.

  Results  Among the 3 cases, 1 was pregnancy with pulmonary embolism and 2 were with mesenteric-portal venous thrombosis. All deep venous thrombosis occurred at first trimester of pregnancy and might have great effect on the prognosis of the maters and fetuses. Doppler ultrasound was the diagnosis method of option for thrombosis, and anticoagulation was the main therapeutic method, similar to the deep venous thrombosis in non-pregnancy. All the 3 patients chose surgical or medical abortion. The medical abortion was performed successfully in 2 patients after the thrombus got stable, and forceps curettage was performed in 1 patient after enterectomy.

  Conclusions  Deep venous thrombosis at specific positions in first trimester is a rare condition. The diagnosis relies on clinical manifestations and examinations. Anticoagulation is the key in treatment, and deep venous thrombosis at different positions may need corresponding thrombolytic or surgicaltreatments. Abortion, if necessary, after stabilization of thrombus will lead to better outcomes.