What is the cause of congenital heart defects?

Congenital heart defects (CHDs) are structural abnormalities of the heart that are present at birth. They occur in about 1 percent of babies and are the most common type of birth defect.

There is no one definitive cause for congenital heart defects, but a variety of factors may play a role, including genetics, environmental exposures, and prenatal infections. Some CHDs may also be caused by problems with how the baby's heart develops in the womb.