If your child has a congenital heart defect, it means that your child was born with a problem in the structure of his or her heart.

Some congenital heart defects in children are simple and don't need treatment. Other congenital heart defects in children are more complex and may require several surgeries performed over a period of several years.

Learning about your child's congenital heart defect can help you understand the condition and know what you can expect in the coming months and years.

Kinser Hanson's story

Mayo Clinic offers congenital heart care: Marcus' story



Serious congenital heart defects usually are noticed soon after birth or during the first few months of life. Signs and symptoms could include:

  • Pale gray or blue skin color (cyanosis)
  • Rapid breathing
  • Swelling in the legs, belly or areas around the eyes
  • Shortness of breath during feedings, leading to poor weight gain

Less-serious congenital heart defects may not be diagnosed until later in childhood. Signs and symptoms of congenital heart defects in older children may include:

  • Easily becoming short of breath during exercise or activity
  • Easily tiring during exercise or activity
  • Fainting during exercise or activity
  • Swelling in the hands, ankles or feet

When to see a doctor

Serious congenital heart defects are often diagnosed before or soon after your child is born. If you notice that your baby has any of the signs or symptoms above, call your child's doctor.

If your child has any of the signs or symptoms of less-serious heart defects as he or she grows, call your child's doctor. Your child's doctor can let you know if your child's symptoms are due to a heart defect or another medical condition.


How the heart works

To understand the causes of congenital heart defects, it may be helpful to know how the heart works.

The heart is divided into four hollow chambers, two on the right and two on the left. To pump blood throughout the body, the heart uses its left and right sides for different tasks.

The right side of the heart moves blood to the lungs through the lung (pulmonary) arteries. In the lungs, blood picks up oxygen then returns to the heart's left side through the pulmonary veins. The left side of the heart then pumps the blood through the body's main artery (aorta) and out to the rest of the body.

How congenital heart defects develop

During the first six weeks of pregnancy, the heart begins to form and starts beating. The major blood vessels that run to and from the heart also begin to develop during this critical time.

It's at this point in your baby's development that heart defects may begin to develop. Researchers aren't sure exactly what causes most of these defects, but they think genetics, certain medical conditions, some medications, and environmental or lifestyle factors, such as smoking, may play a role.

There are many different types of congenital heart defects. They fall into the general categories described below.

Abnormal connections in the heart or blood vessels

Abnormal connections allow blood to flow where it normally wouldn't. Holes in the walls between heart chambers are an example of congenital heart defects that involve an abnormal connection.

An abnormal connection can cause oxygen-poor blood to mix with oxygen-rich blood. This lowers the amount of oxygen sent through your child's body. Your child's skin or fingernails may look blue or pale gray (dusky). The heart and lungs have to work harder to accommodate abnormal blood flow.

Types of abnormal connections in the heart or blood vessels include:

  • Atrial septal defect is a hole between the upper heart chambers (atria).
  • Ventricular septal defect is a hole in the wall between the right and left chambers on the lower half of the heart (ventricles).
  • Patent ductus arteriosus (PAY-tunt DUK-tus ahr-teer-e-O-sus) is a connection between the lung artery and the body's main artery (aorta). It's open while a baby is growing in the mother's womb, and normally closes a few hours after birth. But in some babies, it remains open, causing abnormal blood flow between the two arteries.
  • Total or partial anomalous pulmonary venous connection occurs when all or some of the blood vessels from the lungs (pulmonary veins) attach to a wrong area or areas of the heart.

Congenital heart valve problems

Heart valves are like doorways between the heart chambers and the blood vessels. Heart valves open and close to keep blood moving in the correct direction. If the heart valves can't open and close correctly, blood can't flow smoothly.

Heart valve problems include valves that are narrowed and don't open completely (stenosis) or valves that don't close completely (regurgitation).

Examples of congenital heart valve problems include:

  • Aortic stenosis (stuh-NO-sis). A baby may be born with an aortic valve that has one or two valve flaps (cusps) instead of three. This creates a smaller, narrow opening for blood to pass through. The heart must work harder to pump blood through the valve. Eventually, this leads to enlarging of the heart and thickening of the heart muscle.
  • Pulmonary stenosis. A defect on or near the pulmonary valve narrows the pulmonary valve opening and slows the blood flow.
  • Ebstein anomaly. The tricuspid valve — which is located between the right upper heart chamber (atrium) and the right lower chamber (ventricle) — is malformed and often leaks.

Combination of congenital heart defects

Some infants are born with several heart defects that affect the structure and function of the heart. Very complex heart problems may cause significant changes in blood flow or undeveloped heart chambers.

For example, tetralogy of Fallot (teh-TRAL-uh-jee of fuh-LOW) is a combination of four defects:

  • A hole in the wall between the heart's ventricles
  • A narrowed passage between the right ventricle and pulmonary artery
  • A shift in the connection of the aorta to the heart
  • Thickened muscle in the right ventricle

Other examples of complex congenital heart defects are:

  • Pulmonary atresia. The pulmonary valve is missing, causing abnormal blood flow to the lungs.
  • Tricuspid atresia. The tricuspid valve isn't formed. Instead, there's solid tissue between the right upper heart chamber (atrium) and the right lower chamber (ventricle). This congenital heart defect restricts blood flow and causes the right ventricle to be underdeveloped.
  • Transposition of the great arteries. In this serious, rare heart defect, the two main arteries leaving the heart are reversed (transposed). There are two types. Complete transposition of the great arteries is typically noticed during pregnancy or soon after birth. Levo-transposition of the great arteries (L-TGA) is less common, and symptoms may not be noticed right away.
  • Hypoplastic left heart syndrome. A major part of the heart fails to develop properly. For example, in hypoplastic left heart syndrome, the left side of the heart hasn't developed enough to effectively pump enough blood to the body.

Risk factors

Most congenital heart defects result from problems that occur early as the baby's heart is developing before birth. The exact cause of most congenital heart defects is unknown. However, certain environmental and genetic risk factors may play a role. They include:

  • Rubella (German measles). Having rubella during pregnancy can cause problems in your baby's heart development. Your doctor can test you for immunity to this viral disease before pregnancy and vaccinate you against it if you aren't immune.
  • Diabetes. A woman who had diabetes before getting pregnant can reduce the risk of congenital heart defects by carefully controlling blood sugar before and during pregnancy. Diabetes that develops during pregnancy (gestational diabetes) generally doesn't increase a baby's risk of developing a heart defect.
  • Medications. Certain medications taken during pregnancy may cause birth defects, including congenital heart defects. Give your doctor a complete list of medications you take before trying to become pregnant.

    Medications known to increase the risk of congenital heart defects include thalidomide (Thalomid), angiotensin-converting enzyme (ACE) inhibitors, statins, the acne medication isotretinoin (Absorica, Amnesteem, others), some epilepsy drugs and certain anxiety drugs.

  • Drinking alcohol during pregnancy. Drinking alcohol during pregnancy increases the risk of congenital heart defects.
  • Smoking. If you smoke, quit. Smoking during pregnancy increases the risk of a congenital heart defect in the baby.
  • Family history and genetics. Congenital heart defects sometimes run in families (are inherited) and may be associated with a genetic syndrome. Many children with an extra 21st chromosome (Down syndrome) have heart defects. A missing piece (deletion) of genetic material on chromosome 22 also causes heart defects.


Some possible complications that can occur with a congenital heart defect include:

  • Congestive heart failure. This serious complication may develop in babies who have a significant heart defect. Signs of congestive heart failure include rapid breathing, often with gasping breaths, and poor weight gain.
  • Heart infections. Congenital heart defects can increase the risk of infection of the heart tissue (endocarditis), which can lead to new heart valve problems.
  • Heart rhythm problems. Heart rhythm problems (arrhythmias) can be caused by a congenital heart defect or from scarring that forms after surgery to correct a congenital heart defect.
  • Slower growth and development (developmental delays). Children with more-serious congenital heart defects often develop and grow more slowly than do children who don't have heart defects. They may be smaller than other children of the same age and, if the nervous system has been affected, may learn to walk and talk later than other children.
  • Stroke. Although uncommon, some children with congenital heart defects are at increased risk of stroke due to blood clots traveling through a hole in the heart and on to the brain.
  • Mental health disorders. Some children with congenital heart defects may feel insecure or develop anxiety or stress because of their size, activity restrictions or learning difficulties. Talk to your child's doctor if you're concerned about your child's mental health.


Because the exact cause of most congenital heart defects is unknown, it may not be possible to prevent these conditions. If you have a high risk of giving birth to a child with a congenital heart defect, genetic testing and screening may be done during pregnancy.

There are some things you can do that might reduce your child's overall risk of birth defects such as:

  • Get proper prenatal care. Regular checkups with your doctor during pregnancy can help keep mom and baby healthy.
  • Take a multivitamin with folic acid. Taking 400 micrograms of folic acid daily has been shown to reduce birth defects in the brain and spinal cord and may help reduce the risk of heart defects as well.
  • Don't drink or smoke. These lifestyle habits can negatively affect the baby's health. Also avoid secondhand smoke.
  • Get a rubella (German measles) vaccine. A rubella infection during pregnancy may affect your baby's heart development. Be sure to get vaccinated before you try to get pregnant.
  • Control your blood sugar. If you have diabetes, good control of your blood sugar can reduce the risk of heart defects.
  • Manage chronic health conditions. If you have other health conditions, such as phenylketonuria, talk to your doctor about the best way to treat and manage them.
  • Avoid harmful substances. During pregnancy, have someone else do any painting and cleaning with strong-smelling products.
  • Check with your doctor before taking any medications. Some medications can cause birth defects. Let your doctor know about all the medications you take, including those bought without a prescription.

Congenital heart defects in children care at Mayo Clinic

Aug. 11, 2021
  1. Congenital heart defects (CHD). Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/heartdefects/facts.html. Accessed Feb. 28, 2021.
  2. Congenital heart defects. National Heart, Lung, and Blood Institute. https://www.nhlbi.nih.gov/health-topics/congenital-heart-defects. Accessed Feb. 28, 2021.
  3. Bonow RO, et al. Pericardial diseases. In: Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 11th ed. Elsevier; 2019. https://www.clinicalkey.com. Accessed March 24, 2021.
  4. Overview of congenital cardiovascular anomalies. Merck Manual Professional Version. https://www.merckmanuals.com/professional/pediatrics/congenital-cardiovascular-anomalies/overview-of-congenital-cardiovascular-anomalies. Accessed March 21, 2021.
  5. Tsintoni A, et al. Nutrition of neonates with congenital heart disease: Existing evidence, conflicts and concerns. Journal of Maternal-Fetal & Neonatal Medicine. 2019; doi:10.1080/14767058.2018.1548602.
  6. Hypoplastic left heart syndrome: An overview for primary care providers. Pediatrics in Review. 2019; doi:10.1542/pir.2018-0005.
  7. Donofrio MT, et al. Diagnosis and treatment of fetal cardiac disease: A scientific statement from the American Heart Association. Circulation. 2014; doi:10.1161/01.cir.0000437597.44550.5d.
  8. Riggin EA. Allscripts EPSi. Mayo Clinic. March 25, 2021.
  9. Tinker SC, et al. Use of benzodiazepine medications during pregnancy and potential risk for birth defects, National Birth Defects Prevention Study, 1997-2011. Birth Defects Research. 2019; doi:10.1002/bdr2.1497.
  10. Bacino CA. Birth defects: Causes. https://www.uptodate.com/contents/search. Accessed March 24, 2021.
  11. The impact of congenital heart defects. American Heart Association. https://www.heart.org/en/health-topics/congenital-heart-defects/the-impact-of-congenital-heart-defects. Accessed March 24, 2021.
  12. Pierpoint MA, et al. Genetic basis for congenital heart disease: Revisited: A scientific statement from the American Heart Association. Circulation. 2018; doi:10.1161/CIR.0000000000000606.
  13. Phillips SD (expert opinion). Mayo Clinic. May 4, 2021.