Immunologic disease and fetal death.

Both maternal isoimmunization and maternal autoimmune disease are associated with fetal death. For isoimmunization the immunologic nature of fetal death (hydrops fetalis) is beyond question, but many of the details are poorly understood. It would be extremely helpful to know what immunologic factors are responsible for the wide variation in the degree of fetal hemolysis. This information would surely lead to improved management of isoimmunized pregnancies and create new and more successful therapies for fetuses at risk for hemolysis. The immunology of autoimmune-associated fetal death is, for the most part, an enigma. For the fetal deaths associated with SLE and the antiphospholipid antibodies, demise appears to be a consequence of uteroplacental vascular damage. But the observable pathology is nonspecific, and the evidence for a direct immunologic mechanism is sparse. The similarity between the uteroplacental vascular lesions found with these autoimmune conditions and those seen in preeclampsia demands more intensive investigation. For the fetal deaths caused by complete congenital heart block associated with maternal autoantibodies, the evidence for a direct immunologic mechanism is now being established. As with isoimmunization, a more complete understanding of autoimmune-associated fetal death will open new avenues of management and therapy.