Congenital heart defects (CHDs) are structural abnormalities present at birth that affect the heart's function. CHDs are the most common type of birth defect, affecting approximately 1% of live births. There are many types of CHDs, ranging from simple defects that do not require treatment to complex defects that require surgery or other interventions.

Symptoms of CHDs vary depending on the type and severity of the defect but can include poor feeding, poor growth, bluish skin or lips, shortness of breath, and fatigue. Diagnosis is typically made through a physical exam, echocardiogram, and other imaging tests.

Treatment for CHDs depends on the type and severity of the defect. Some CHDs may not require treatment and may improve on their own over time, while others may require medications, surgery, or other interventions. In some cases, multiple surgeries may be required over a period of years to correct the defect and improve heart function.

With advances in medical technology and treatment options, the prognosis for children with CHDs has improved significantly in recent years. Many children with CHDs are able to lead normal, healthy lives with proper treatment and ongoing medical care.

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.

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.

Treatment of congenital heart defects in children depends on the specific type of heart problem and how severe it is. Sometimes, a congenital heart defect may have no long-term effect on your child's health and may safely go untreated. Certain defects, such as small holes, may close as your child ages.

Serious heart defects require treatment soon after they're diagnosed. Treatment may involve medications, heart procedures or a heart transplant.

Medications

Medications may be given to treat symptoms or complications of a congenital heart defect and may be used alone or with a heart procedure. Medications for congenital heart defects include:

• Blood pressure drugs. Examples include angiotensin-converting enzyme (ACE) inhibitors, angiotensin II receptor blockers (ARBs) and beta blockers.
• Diuretics. This type of medication reduces the amount of fluid in the body, which reduces the strain on the heart.
• Heart rhythm drugs. These medications, called anti-arrhythmics, help control an abnormal heartbeat (arrhythmia).

Surgery or other procedures

If your child has a severe congenital heart defect, a heart procedure or surgery may be recommended. Heart procedures and surgery done to treat congenital heart defects include:

• Fetal cardiac intervention. Rarely, if a serious defect is diagnosed before birth, a procedure can be done during pregnancy to correct the problem or help reduce complications of the defect as the child grows. Fetal cardiac intervention is rarely performed and only possible in very specific circumstances.
• Cardiac catheterization. Some children and adults have their congenital heart defects repaired using thin, flexible tubes (catheters). Cardiac catheterization can be used to fix holes in the heart or areas of narrowing without open-heart surgery.
• During cardiac catheterization, the doctor inserts one or more catheters into a blood vessel, usually in the groin, and to the heart. Tiny tools are threaded through the catheter to the heart to repair the defect. Some catheter procedures have to be done in steps over a period of years.
• Heart surgery. Your child may need open-heart surgery or minimally invasive heart surgery to repair a congenital heart defect.
• Heart transplant. If a serious heart defect can't be repaired, a heart transplant may be needed.