Thrombophilia might be the essential pathogenetic mechanism of thromboembolism associated with pregnancy. Venous thromboembolism during or after assisted reproductive technologies is predicted to emerge due to increased number of women undergoing this technique. Low molecular weight heparins was effective for preventing recurrent thromboembolism and severe obstetric complications. Women with personal or family history of thromboembolism or with history of obstetric complications should be screened for thrombophilia.