Symptoms and causes

Symptoms

Serious congenital heart defects usually become evident 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, abdomen 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, because your child may not have any noticeable signs of a problem. If signs and symptoms are evident in older children, they 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.

Causes

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 vessels called 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 aorta and out to the rest of the body.

How heart defects develop

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

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 factors, such as smoking, may play a role.

Types of heart defects

There are many different types of congenital heart defects, falling mainly into these categories:

  • Holes in the heart. Holes can form in the walls between heart chambers or between major blood vessels leaving the heart.

    In certain situations, these holes allow oxygen-poor blood to mix with oxygen-rich blood, resulting in less oxygen being carried to your child's body. Depending on the size of the hole, this lack of sufficient oxygen can cause your child's skin or fingernails to appear blue or possibly lead to congestive heart failure.

    A ventricular septal defect is a hole in the wall between the right and left chambers on the lower half of the heart (ventricles). An atrial septal defect occurs when there's a hole between the upper heart chambers (atria).

    Patent ductus arteriosus (PAY-tunt DUK-tus ahr-teer-e-O-sus) is a connection between the pulmonary artery (containing deoxygenated blood) and the aorta (containing oxygenated blood). A complete atrioventricular canal defect is a condition that causes a hole in the center of the heart.

  • Obstructed blood flow. When blood vessels or heart valves are narrow because of a heart defect, the heart must work harder to pump blood through them. Eventually, this leads to enlarging of the heart and thickening of the heart muscle. Examples of this type of defect are pulmonary stenosis or aortic stenosis (stuh-NO-sis).
  • Abnormal blood vessels. Several congenital heart defects happen when blood vessels going to and from the heart don't form correctly, or they're not positioned the way they're supposed to be.

    A defect called transposition of the great arteries occurs when the pulmonary artery and the aorta are on the wrong sides of the heart.

    A condition called coarctation of the aorta happens when the main blood vessel supplying blood to the body is too narrow. Total anomalous pulmonary venous connection is a defect that occurs when blood vessels from the lungs attach to wrong area of the heart.

  • Heart valve abnormalities. If the heart valves can't open and close correctly, blood can't flow smoothly.

    One example of this type of defect is called Ebstein's anomaly. In Ebstein's anomaly, the tricuspid valve — which is located between the right atrium and the right ventricle — is malformed and often leaks.

    Another example is pulmonary atresia, in which the pulmonary valve is missing, causing abnormal blood flow to the lungs.

  • An underdeveloped heart. Sometimes, a major portion 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.
  • A combination of defects. Some infants are born with several heart defects. 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, and thickened muscle in the right ventricle.

Risk factors

Most congenital heart defects result from problems early in your child's heart development, the cause of which 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. You can reduce the risk of congenital heart defects by carefully controlling your diabetes before attempting to conceive and during pregnancy. Gestational diabetes generally doesn't increase your 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 attempting 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, Claravis) and lithium.

  • Drinking alcohol during pregnancy. Avoid alcohol during pregnancy because it increases the risk of congenital heart defects.
  • Smoking. Smoking during pregnancy increases the likelihood of a congenital heart defect in the baby.
  • Heredity. Congenital heart defects sometimes run in families and may be associated with a genetic syndrome. Many children with Down syndrome — which is caused by an extra 21st chromosome (trisomy 21) — have heart defects. A missing piece (deletion) of genetic material on chromosome 22 also causes heart defects.

    Genetic testing can detect such disorders during fetal development. If you already have a child with a congenital heart defect, a genetic counselor can estimate the odds that your next child will have one.

Complications

Some potential 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.
  • Slower growth and development. 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.
  • 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.
  • Cyanosis. If your child's heart defect causes oxygen-poor blood to mix with oxygen-rich blood in his or her heart, your child may develop a grayish-blue skin color, a condition called cyanosis.
  • 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.
  • Emotional issues. Some children with congenital heart defects may feel insecure or develop emotional problems because of their size, activity restrictions or learning difficulties. Talk to your child's doctor if you're concerned about your child's moods.
  • A need for lifelong follow-up. Children who have heart defects should be mindful of their heart problems their entire lives, as their defect could lead to an increased risk of heart tissue infection (endocarditis), heart failure or heart valve problems. Most children with congenital heart defects will need to be seen regularly by a cardiologist throughout life.