[Hereditary antithrombin deficiency resulting in severe neonatal thrombosis].

We report a severe vena cava inferior thrombosis in a mature two day-old boy. Pregnancy and birth were event free. The mother had antithrombin deficiency. During pregnancy she was treated with enoxaparin and just before delivery with 2000 IE antithrombin concentrate. At admission the child had unmeasurable antithrombin and low protein C concentrations. He was treated with antithrombin concentrate and heparin. The thrombus disappeared, and now he is on maintenance treatment with warfarin. Risk factors and treatment of inherited antithrombin deficiency are discussed.