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.

CHB is an abnormal condition in which the heart beats slowly. This is a disease that is strongly associated with maternal antibodies to SSA/Ro and SSB/La ribonucleoproteins. This study hopes to clarify the causes of CHB and develop appropriate treatments. The study has two parts.

The first part of the study will be prospective; it will determine if fluorinated steroids given to women prior to birth improves the heart function and well-being of their newborns. This part of the study will evaluate fetuses diagnosed in utero with CHB during the third trimester of pregnancy. Diagnosis of CHB must occur at least 6 weeks before the baby is born to allow for sufficient data collection. It will be the decision of the physician and the mother as to whether a steroid will be administered. Fetuses will be evaluated before delivery by electrocardiogram (ECG) to detect abnormal fluid collection and by ultrasound to monitor heartbeat. After birth, newborns will be assessed for overall pumping strength of the heart and for abnormal heartbeat. Blood will be drawn from the mother at the time of enrollment and during delivery. Visits will occur over a span of approximately 5 months.

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.

For both parts of the study, babies will undergo ECGs after delivery and at one year of age. Additional tests not related to the study may be ordered by the physician.

Inclusion Criteria for Prospective Part of Trial:

• Mother must have anti-Ro and/or anti-La antibody
• Fetal bradyarrhythmia (slow, abnormal heart rhythm)

Exclusion Criteria for Prospective Part of Trial:

• Fetal heart abnormalities that may cause newborn CHB and could account for atrioventricular (AV) block

Inclusion Criteria for Observational Part of Trial:

• Mother must have anti-Ro and/or anti-La antibody
• Fetus must have documented normal heartbeat prior to the 16th week of pregnancy
• Fetus must have a structurally normal heart
• Mother must be enrolled during the 16th, 17th, or 18th week of pregnancy

Exclusion Criteria for Observational Part of Trial:

• Mother is taking more than 10 mg of prednisone per day