Fetal Congenital Complete Atrioventricular Block in a Mother with Isolated Serum Anti-SSA/Ro and Anti-SSB/La Antibodies

Abstract

Congenital atrioventricular block (AVB) is rare but carries a significant fetal or neonatal mortality and morbidity. In about half of the cases, it is associated with a congenital structural heart anomaly and often results from the transplacental transfer of maternal anti-SSA/Ro and/or anti- SSB/La autoantibodies in women with autoimmune diseases. We report a case of an isolated congenital AVB with cardiomegaly and pericardial effusion in a woman who had both serum anti- SSA/Ro and anti-SSB/La antibodies, but had no clinical or laboratory evidence of autoimmune diseases. The mother was treated with oral dexamethasone for about 10 days antenatally until the fetal pericardial effusion regressed. AVB persisted without any fetal compromise throughout the remaining gestational period until elective cesarean delivery at term. A permanent pacemaker was implanted into the baby at 2 weeks after birth due to hypotension and aggravating heart failure. The baby did not develop any complications and was discharged from the hospital.