Some newborns are born with congenital heart block (CHB), a condition occurring in babies with neonatal lupus. The first part of the study will test the effectiveness of fluorinated steroids, including dexamethasone, in improving the heart function and general health of newborns who have auto-antibody-associated CHB. The second part of this study will use ultrasound and heart monitoring to observe high-risk pregnant women and their fetuses during the third trimester of pregnancy.