Intrauterine therapy for presumptive fetal myocarditis with acquired heart block due to systemic lupus erythematosus. Experience in a mother with a predominance of SS-B (La) antibodies.

An experimental therapeutic regimen for congenital lupus erythematosus, which consists of treating the mother with high doses of dexamethasone and performing plasmapheresis (3 times per week), was developed. This regimen was administered to a woman whose pregnancy was complicated by the abrupt onset of fetal pericarditis, myocarditis, and complete heart block in the twenty-fourth week of gestation. The effectiveness of plasmapheresis was evidenced by a decrease in the very high titer of SS-B (La) antibodies in the mother. After 5 weeks of therapy, the cardiac disease was ameliorated. The infant tolerated delivery at week 31, and the heart block has persisted. The rationale for this therapy for fetal disease is discussed, with emphasis on 2 goals: to diminish the quantity of maternal antibody that is transmitted to the fetus, and to suppress the manifestations of fetal carditis with the use of glucocorticoids that are not inactivated by the placenta. Tentative recommendations for more intensive prenatal monitoring of maternal and fetal status for those at risk are outlined.