Understand Your Risk for Congenital Heart Defects

Grandfather and baby grandson reading a book together

Over 1.3 million Americans alive today have some form of congenital heart defect (CHD). In the United States, about 40,000 children are born with a heart defect each year. At least eight of every 1,000 infants born each year have a heart defect.

The causes of congenital heart defects are still being researched, but scientists and physicians are making progress.

Causes of heart defects

Unknown cause

The exact cause of most heart defects isn’t known. Although it’s presumed to be genetic, only a few genes have been linked to heart defects. That means heart defects are likely due to a combination of multiple genetic and environmental factors.

There’s usually a 2 to 15 percent chance of a heart defect recurring in a family. The odds depend on what type of defect is present and whether anyone else in your family has a heart defect.

Genetic syndrome

Some people with congenital heart defects have a specific genetic condition that can include other health problems. They may or may not be aware that they have such a condition.

The chances that people with this genetic condition will pass it along to their child can be as high as 50 percent. These conditions can vary widely in their severity, so children may have less serious or more serious health problems than their parents.

Learn more about genetic counseling.

Single gene

Rarely, congenital heart defects are caused by changes in a single gene. Often, when this is the case, more than one person in the family has a heart defect. The chances that another family member will have a heart defect can be as high as 50 percent.

Environmental exposure

Heart defects can also be caused by something your mother was exposed to during pregnancy, such as an infection or a drug. If you have such an environmentally caused defect, the chances that your children will have a heart defect is no higher than average, which is quite low.

Taking part in research

If you’re an adult with a congenital heart defect, you may be able to help improve the medical community’s understanding of such defects by taking part in research.

Participating in research could help your family and other families better understand specific heart defects and whether those issues are likely to be passed from parent to child. It’s also possible that future research will discover the causes of heart defects.

Ask your genetic counselor about research studies you could take part in.