Fetal Effects of Autoimmune Disease

Two mechanisms may provoke the maternal immune system during pregnancy. First, fetal blood cells that enter the maternal circulation are recognized as antigens and may provoke an immune response and the production of immunoglobulins. Maternal antibodies cross the placenta and may destroy fetal cells. Second, autoantibodies from the mother's immune system provoked by an autoimmune disorder may cause fetal or neonatal complications. The common denominators of such disorders are the production of IgG in the maternal compartment, the transfer of IgG through the placenta, and the effects of these antibodies in the fetal compartment or neonate. This chapter discusses immune thrombocytopenic purpura (ITP), neonatal alloimmune thrombocytopenia, fetal-neonatal consequences of maternal antinuclear and antiphospholipid antibodies, myasthenia gravis, and pemphigoid gestationis. Therapy before birth and in the neonatal period includes mainly steroids and intravenous immunoglobulins. Biologic treatments have become more commonly used despite limited safety data during pregnancy. The obstetrical approach should consider the potential risk for the fetus during childbirth and hence tailor the best mode of delivery.