One of the strongest clinical associations with autoantibodies against components of the SSA/Ro-SSB/La ribonucleoprotein complex is the development of congenital heart block in an offspring, an alarming prospect facing 2% of primigravid mothers with these reactivities. This risk is increased tenfold in women who have had a previous child with congenital heart block. Accumulated evidence suggests that anti-SSA/Ro and anti-SSB/La antibodies are necessary but insufficient for fetal disease. Basic and clinical research is heavily focused on identifying fetal and environmental factors that convert disease susceptibility to disease development. A disturbing observation that has emerged from current research efforts is the rapidity of disease progression, with advanced heart block and life-threatening cardiomyopathy being observed less than 2 weeks after detection of a normal sinus rhythm. Once third-degree block is unequivocally identified, reversal has never been achieved, despite dexamethasone treatment. Accordingly, strategies aimed at preventing disease before irrevocable scarring ensues assume a high priority. One approach has been the implementation of serial echocardiography to monitor for a prolonged PR interval. Intravenous immunoglobulin is being evaluated as a potential prophylactic approach in mothers who have previously had an affected child.