The second part of this study will be observational; the purpose is to identify classic indicators of heartbeat dysfunction and heart injury in newborns with CHB. The goal of this part of the study is to better understand the stages of heart injury, the role of anti-Ro/La antibodies in CHB, and procedures that may reverse heart block. Mothers considered to be at high risk for having a child with CHB will undergo weekly ECGs from 16 weeks into their pregnancy until Week 24, then will have an ECG every other week from Week 24 through Week 34. There will be a total of 15 visits to conduct these ECGs. Blood will be drawn at the first ECG visit and during delivery. Visits will occur over a span of 4 months.