Fetuses and infants of women with anti-SSA/Ro and anti-SSB/La antibodies are at risk of neonatal lupus syndrome, featuring skin lesions, hematological and hepatic disorders, and congenital heart block (CHB) in the absence of severe cardiac malformation. The prevalence of CHB in newborns of anti-SSA/Ro positive women with known connective tissue disease is 1 to 2% and the risk of recurrence ranges from 10 to 17%. CHB is definitive and is associated with significant morbidity (pacemaker must be implanted in 2/3 of cases) and mortality (16 to 19%). Myocardial involvement may either be associated or appear subsequently. Other manifestations are discussed. For anti-SSA/Ro positive pregnant women, echocardiograms should be performed every 2 weeks from 16 to 24 weeks of gestation, and every week in case of past history of CHB. Electrocardiogram should be performed in the first days of life for all children to detect incomplete CHB. Therapy for CHB detected in utero is based on fluorinated steroids, especially betamethasone. Its efficiency is variable.