Transient Recovery of Complete Atrioventricular Block Due to Maternal Anti-SS-A Antibody Through Antenatal Steroid Administration After 27 Weeks of Gestation

Maternal anti-SS-A antibodies may cause complete atrioventricular block or myocardial damage in a fetus. Effective treatment for this has not been established. Although antenatal steroids may be a treatment option for anti-SS-A antibody-related myocarditis or atrioventricular block, a complete atrioventricular block is usually considered irreversible once established. Previous reports have indicated that, in cases where antenatal steroids were effective for atrioventricular block, they were administered earlier in the pregnancy. Here we present a case where maternal steroid administration initiated from 27 weeks, which is beyond the recommended optimal treatment period, was effective in altering a complete atrioventricular block to a grade I atrioventricular block.