Congenital heart block affects 2% of all mothers with anti-Ro/La antibodies, can cause heart failure in utero, and has a 20% mortality rate in the first 3 years of life. Maternal fluorinated steroids to prevent or reverse congenital heart block can cause pregnancy complications. Intravenous immunoglobulin (IVIG) has been given with maternal steroids to prevent the recurrence of congenital heart block, although its efficacy is unproven.
We report the use of IVIG to prevent progression of 2:1 congenital heart block with intermittent complete heart block. After two maternal infusions of IVIG (0.4 g/kg) at 31 weeks of gestation, the fetal heart rate reverted to long periods of sinus rhythm, which was sustained until postnatal life.
Our case supports investigating IVIG in the prevention or treatment of this life-threatening condition.