Isolated Iliac Vein Thrombosis During Oral Contraceptive Therapy in Three "Normal" Women

Isolated iliac vein thrombosis appears to be a rare clinical entity. It is usually due to extrinsic compression on the iliac vein with consequent stasis. Diagnosis may be difficult since compression ultrasonography is usually negative. Only phlebography is surely diagnostic. This procedure should be carried out whenever there is a discrepancy between the clinical evaluation and a negative sonography. We report three women on oral contraceptive therapy in whom a diagnosis of isolated iliac vein thrombosis was suspected clinically and confirmed phlebographically. No other congenital or acquired potential cause of thrombosis was present in the propositae but for the oral contraceptives. Oral contraceptives had been taken for 12, 3, and 2 months respectively for three patients before thrombosis occurred. Two of the propositae were 25 years old and the third was 54. The latter patient had been given oral contraceptives to "prevent osteoporosis" after menopause. The discontinuation of the pill together with usual heparin and coumarin therapy were effective in every instance. A specific pathogenic role of the oral contraceptives may be surmised. In fact, no isolated iliac vein thrombosis was found in a control group of 20 women of fertile age we showed to have idiopathic deep vein thrombosis of the legs. This article emphasizes once again the importance of a careful clinical evaluation in the suspicion of deep vein thrombosis. Key Words: Oral contraceptive therapy-Deep vein thrombosis-Iliac vein thrombosis.