Congenital heart disease is a structural problem with the heart that develops before birth

Congenital heart disease means the heart or blood vessels connected to it formed abnormally while the fetus was developing in the womb. The defect is present at birth, though it may not be detected immediately. Some congenital heart defects are minor and cause no symptoms; others are severe and affect how blood flows through the heart and lungs from the moment a child is born.

The heart normally has four chambers and four valves that work together to pump blood to the lungs and the rest of the body in a specific sequence. In congenital heart disease, one or more of these structures may be missing, too small, too large, or connected in the wrong place. This changes the path blood takes and can mean some blood bypasses the lungs or the body doesn't receive enough oxygen-rich blood.

Congenital heart defects are the most common birth defect in the United States. They range from simple holes between chambers (which may close on their own) to complex arrangements where the major blood vessels are switched or the heart has only one functional chamber instead of four.

Key Takeaways

  • Congenital heart disease is a structural abnormality of the heart or its blood vessels that forms before birth and is present from the moment a child is born.
  • The defect occurs when the heart chambers, valves, or major blood vessels develop in an abnormal shape, size, or position during fetal development.
  • Some congenital heart defects cause no symptoms and may never require treatment, while others cause breathing problems, poor feeding, or bluish skin color in infants.
  • Doctors detect congenital heart disease through physical examination, heart murmur detection, chest X-rays, echocardiograms, or prenatal ultrasound.
  • Treatment depends on the type and severity of the defect and may range from monitoring to medication to surgery.

How the heart normally develops and what goes wrong

The fetal heart begins forming around the third week of pregnancy and continues developing throughout the first three months. During this time, the heart tube folds, chambers divide, and valves form. If something disrupts this process—whether a genetic factor, an infection the mother had, or exposure to certain medications—the heart may not develop correctly.

The exact cause of most congenital heart defects is unknown. Some are linked to genetic conditions like Down syndrome or Turner syndrome. Others are associated with maternal infections (such as rubella), maternal diabetes, or maternal use of certain medications like isotretinoin (used for severe acne). In many cases, no clear cause is identified.

The defect itself is fixed—it does not develop or worsen after birth because the heart structure is already formed. However, the body's response to the defect can change over time as the child grows and the demands on the heart increase.

Common types of congenital heart defects

Atrial septal defect (ASD) is a hole in the wall between the two upper chambers of the heart. Blood flows from the left atrium to the right atrium, meaning some oxygen-rich blood bypasses the body and goes back to the lungs. Many ASDs are small and cause no symptoms.

Ventricular septal defect (VSD) is a hole in the wall between the two lower chambers. It is the most common congenital heart defect. Small VSDs may close on their own; larger ones allow too much blood to flow to the lungs and can cause heart strain.

Patent ductus arteriosus (PDA) occurs when a blood vessel that normally closes after birth remains open. This vessel, called the ductus arteriosus, allows blood to bypass the lungs before birth. If it stays open, extra blood flows to the lungs and heart.

Tetralogy of Fallot is a combination of four defects: a hole between the ventricles, a narrowed pulmonary valve, a thickened right ventricle wall, and the aorta positioned over the hole instead of the left ventricle. Infants with this defect often have bluish skin because oxygen-poor blood reaches the body.

Transposition of the great arteries means the two main arteries leaving the heart are switched. The aorta arises from the right ventricle and the pulmonary artery from the left, reversing the normal flow. This is life-threatening without treatment because the body receives oxygen-poor blood.

Signs and symptoms in infants and children

Some infants show signs of congenital heart disease within hours or days of birth. Others have no symptoms for months or years. The symptoms depend on the type of defect and how much it disrupts normal blood flow.

Newborns with severe defects may have cyanosis—a bluish tint to the skin, lips, or fingernails—because their blood does not carry enough oxygen. They may breathe rapidly, feed poorly, or fail to gain weight. Some are unusually tired or have difficulty keeping up with normal activity as they grow older.

A doctor may hear an abnormal heart sound called a heart murmur during a routine physical examination. Not all murmurs indicate disease, but some are caused by turbulent blood flow from a congenital defect. Other signs include swelling in the legs or abdomen, shortness of breath, or chest pain during exercise.

How congenital heart disease is detected

Congenital heart disease can be found before birth, at birth, or later in childhood. Prenatal ultrasound performed during the second trimester can show some major defects, though not all are visible on ultrasound.

After birth, a physical examination and listening for a heart murmur are often the first steps. If a murmur or other sign is present, the doctor may order an echocardiogram—an ultrasound of the heart that shows its structure and how blood flows through it. This is the primary tool for diagnosing congenital heart defects and is painless and non-invasive.

A chest X-ray may show whether the heart is enlarged or whether there is extra fluid in the lungs. An electrocardiogram (ECG) records the heart's electrical activity. In some cases, cardiac catheterization—a procedure in which a thin tube is threaded into the heart—is used to measure pressures and oxygen levels in different chambers.

Treatment options based on severity

Treatment depends on which defect is present, how severe it is, and how much it affects the child's health. Some defects require no treatment at all. Others need medication to help the heart work more efficiently or to prevent complications. Still others require surgery.

Small ASDs and VSDs often close on their own as the child grows, so doctors may simply monitor them with regular echocardiograms. If a defect does not close and causes symptoms or puts strain on the heart, surgery or a catheter-based procedure may be recommended.

Medications such as diuretics (water pills) can reduce fluid buildup if the heart is not pumping efficiently. Antibiotics may be prescribed before dental work or surgery to prevent infection of the heart lining in children with certain defects.

Surgery to repair or reconstruct the defect is performed when the benefit outweighs the risk. Some children need surgery in infancy; others can wait until they are older. Advances in surgical technique and catheter-based interventions have made it possible to repair many defects that were once considered untreatable.

Living with congenital heart disease into adulthood

Most children born with congenital heart disease now survive into adulthood because of improved detection and treatment. However, they require ongoing monitoring throughout their lives. Even after successful surgery, the heart may not function exactly as a normal heart does, and complications can develop years later.

Adults with congenital heart disease should see a cardiologist regularly, even if they feel well. They may need to limit strenuous exercise, take medications long-term, or have repeat procedures. Pregnancy in women with congenital heart disease carries additional risks and requires specialized care.

Many people with congenital heart disease live full, active lives. The key is understanding the specific defect, following medical recommendations, and staying informed about how the condition may change over time.

Frequently Asked Questions

Can congenital heart disease be prevented?

Most congenital heart defects cannot be prevented because the cause is unknown in the majority of cases. However, pregnant people can reduce some risk by avoiding certain medications, managing diabetes, and getting vaccinated against infections like rubella before pregnancy.

Is congenital heart disease hereditary?

Most congenital heart defects are not inherited, but some run in families. If a parent has congenital heart disease, the risk to their child is higher than in the general population. Genetic counseling can help families understand their risk.

Do all babies with congenital heart disease need surgery?

No. Many defects are mild and require only monitoring. Others close on their own as the child grows. Surgery is recommended when the defect causes symptoms, limits activity, or puts strain on the heart.

What is the difference between congenital and acquired heart disease?

Congenital heart disease is present from birth due to abnormal development. Acquired heart disease develops later in life from causes like infection, high blood pressure, or coronary artery disease.

Can congenital heart disease be detected on a regular ultrasound during pregnancy?

Some major defects can be seen on a detailed ultrasound performed in the second trimester, but not all congenital heart defects are visible prenatally. Many are only discovered after birth during a physical examination or when symptoms appear.