Intravenous immunoglobulins, first given to recurrent aborters with anti-phospholipid syndrome, have been administered to unexplained aborters since 1986. They probably have immunomodulatory properties beyond supplying blocking antibodies. When pregnancy was confirmed, women were started with a loading dose which was repeated every 3-4 weeks until the second trimester. Dosages were empirical. Pregnancy rates ranged between 50 and 82%. The main maternal complications, i.e. allergic reactions and infections, were rare.