Genetics and Congenital Heart Defects

Genetics and Congenital Heart Defects

A congenital heart defect (CHD) is the most common type of birth defect. It is estimated that 2 to 3 million people in the United States have a CHD.

Over the last few decades, treatments for CHDs have improved—meaning more children born with a CHD are growing up to have children of their own.

If you have a CHD, you might wonder what the risk is for your child to also have a CHD. You might also wonder whether pregnancy will affect your health. These are very important questions to discuss with your congenital cardiologist and perhaps other specialists, such as a maternal-fetal-medicine specialist and a geneticist or genetic counselor.

What causes a congenital heart defect?

CHDs are caused by genetics, the environment, or a combination of both. Some known genetic causes include:

  • Chromosome abnormalities: Extra or missing chromosomes.
  • Gene mutation: A change to the DNA sequence or order that makes up a gene.

About genetic testing:

There are two types of tests used with genetic testing: chromosomal and DNA. Recent advances in these tests have made it more possible to find the genetic cause of CHDs for many patients. Sometimes, however, a genetic change cannot be identified, but the cause can still be genetic.

How to reduce your baby’s risk of a congenital heart defect:

If you have a CHD, your baby has a higher risk of being born with a CHD. In fact, there is about a 5% chance your child will have a CHD, too. A geneticist or genetic counselor can help you determine if genetic testing might be helpful for you prior to becoming pregnant. See Preconception Counseling for Women with a Congenital Heart Defect for more information.

You might be asking yourself:

  • What can I do to lower my baby’s chance of being born with a CHD?
  • How might I be able to improve my baby’s outcome if he or she has a CHD? 

These are important questions to ask your medical care team, but some research suggests taking folate prior to conception and during pregnancy may decrease the risk of a CHD.

How a congenital heart defect is diagnosed in an unborn baby:

A CHD can be diagnosed very early in pregnancy (around 18 to 20 weeks) via an ultrasound of the baby’s heart, called a fetal echocardiogram.

If you have a CHD caused by a genetic change, your maternal-fetal-medicine specialist can perform either an amniocentesis or chorionic villus sampling to determine whether your unborn baby has the same genetic change. Both of these tests are done by inserting a needle into the womb to get a small tissue sample for testing

Additional information regarding congenital heart defects and lifelong cardiac care is available at the Congenital Heart Public Health Consortium (CHPHC) website, www.chphc.org. The CHPHC is housed at the American Academy of Pediatrics through a grant from the Centers for Disease Control and Prevention in an effort to utilize public health principles to affect change for those whose lives are impacted by a CHD. Organizational members of the Consortium represent the voice of providers, patients, families, clinicians and researchers.

Last Updated 11/7/2016