What Causes Holes in the Heart?

Mothers of children born with an atrial septal defect (ASD), a ventricular septal defect (VSD), or another type of heart defect often think that they did something wrong during the pregnancy to cause the problem. However, most of the time, doctors don't know why these congenital heart defects develop.

Heredity may play a role in some heart defects. For example, a parent who has a congenital heart defect is slightly more likely than other people to have a child with the problem. In very rare cases, more than one child in a family is born with a heart defect. Children with genetic defects often have congenital heart defects. An example of this is Down syndrome—half of all babies with Down syndrome have congenital heart defects.

Scientists continue to search for the causes of congenital heart defects.