Understand the Risk for Congenital Heart Disease

Jackson (second from left) was born with tricuspid atresia, hypoplastic right ventricle, atrial septal defect and a ventricular septal defect.

Congenital heart defects are the most common type of birth defect. In the United States, nearly 1% of babies are born with a heart defect each year. Most congenital heart defects can be treated, even when they are severe.

Researchers continue to study what causes congenital heart defects. While many questions remain, scientists and healthcare professionals are learning more every year.

What causes heart defects?

Unknown cause

The exact cause of most heart defects isn’t known. Researchers believe that genetic, environmental and other factors may contribute to the development of many heart defects.

Heart defects can sometimes happen more than once in a family. The chance of recurrence depends on the type of defect and whether other family members have a heart defect.

Genetic syndrome

Some people with congenital heart defects have a genetic condition that can affect other parts of the body. They may not know they have this condition until testing is done.

In some genetic conditions, a parent who carries a disease-causing genetic variant may have up to a 50% chance of passing it on to each child. Whether a child who inherits the genetic variant will develop a heart defect, and how severe it may be, can vary.

Learn more about genetic counseling.

Single gene

A small percentage of congenital heart defects are caused by changes in a single gene. When this happens, other family members may also have the condition. The chance of passing a genetic condition to a child depends on how the condition is inherited.

Environmental factors

Sometimes a congenital heart defect can be linked to something a mother was exposed to during pregnancy, such as an infection or certain medications. An environmental exposure is generally not passed from parent to child. However, other genetic factors may still affect the chance of a heart defect occurring in a family.

Taking part in research

If you’re an adult with a congenital heart defect, you may be able to help researchers learn more about heart defects by taking part in research.

Research can help families better understand specific heart defects and how they may affect future generations. It may also help researchers learn more about what causes heart defects.

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