Abstract
Twenty-six-year old woman developed wide ecchymoses in the arms 3 months after the second postpartum. The plasma of the patient had the inhibitor against factor VIII activity, and it was immunoglobulin G. She was first treated with prednisolone, but the effect was insufficient. She was subsequently treated with factor VIII concentrate. The inhibitor disappeared, and the activity of factor VIII returned to almost normal after 9 months.