American Board of Internal Medicine (ABIM) Certification Practice Exam

What percentage of pregnancies are affected by neonatal congenital heart block if the mother is positive for specific antibodies?

1. 1%

2. 2%

3. 5%

4. 10%

The correct answer is: 2%

Neonatal congenital heart block is a rare but significant condition that can occur in newborns when the mother has specific antibodies associated with autoimmune diseases, such as Sjögren's syndrome or systemic lupus erythematosus. The relevant antibodies are mainly anti-Ro (SS-A) antibodies, which can cross the placenta and impact fetal heart conduction. Research indicates that approximately 2% of pregnancies are affected by neonatal congenital heart block when the mother tests positive for these specific antibodies. This percentage, while relatively low, highlights the importance of screening and monitoring for mothers with known autoimmune conditions to assess the risk of fetal complications, including congenital heart block. Early diagnosis and appropriate management strategies are crucial for ensuring better outcomes for affected infants. Understanding this statistic emphasizes the need for healthcare providers to be aware of the potential risks associated with maternal autoimmune antibodies during pregnancy and to provide adequate counseling and monitoring for expecting mothers.