Failure of intravenous immunoglobulin to prevent congenital heart block: Findings of a multicenter, prospective, observational study.

OBJECTIVE: Congenital heart block (CHB) is presumed to be caused by transplacental passage of maternal immunoglobulin against Ro and La ribonucleoproteins. The recurrence rate in subsequent pregnancies following the birth of a child with CHB is approximately 19%. The purpose of this study was to determine whether intravenous immunoglobulin (IVIG) therapy could prevent the development of CHB in the fetuses of high-risk pregnant women. METHODS: A total of 24 pregnancies in 22 women who had a previous pregnancy in which CHB developed, were over the age of 18 years, were