May-Thurner syndrome resulting in acute iliofemoral deep vein thrombosis in the postpartum period

BACKGROUND: May-Thurner Syndrome is a congenital anomaly of the right iliac artery, which causes an acquired narrowing defect in the left iliac vein. The artery abnormally compresses the vein causing intraluminal collagen deposition and sluggish venous flow. This syndrome places patients at increased risk of proximal deep venous thrombosis. CASES: We describe three postpartum patients with May-Thurner Syndrome complicated by iliofemoral deep vein thrombosis and their management. There was no evidence of underlying thrombophilia, yet these women had large proximal thrombi. They were treated with anticoagulation followed by thrombolysis and, in one case, stent placement. CONCLUSION: May-Thurner syndrome can predispose postpartum patients to large, proximal thrombi and may be treated effectively with a combination of thrombolysis and stent placement. May-Thurner Syndrome should be considered in the differential diagnosis of pelvic thrombosis, especially when thrombophilias are excluded.