Health Topic

Congenital Heart Defects

Congenital heart defects, problems with the structure of the heart, are the most common type of birth defect. Learn about diagnosis and treatment.

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About Congenital Heart Defects

Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth. These defects happen when a fetus's heart doesn't develop normally during pregnancy. Congenital heart defects are the most common type of birth defect.

Congenital heart defects can change the way the heart pumps blood. They may make blood flow too slowly, go the wrong way, or block it completely.

There are many types of congenital heart defects. They can happen in one or more parts of the heart. The most common types are:

  • Septal defects ("hole in the heart") - openings in the wall between the left and right sides of the heart
  • Heart valve defects - problems with the valves that control the flow of blood through the heart
  • Defects in the large blood vessels that carry blood in and out of the heart

Congenital heart defects can range from very mild problems that never need treatment to life-threatening problems at birth. The most serious congenital heart defects are called critical congenital heart disease. Babies with these defects usually need surgery in the first year of life. But the symptoms of milder heart defects may not show up until childhood or adulthood.

Researchers often don't know what causes congenital heart defects. They do know that changes in a baby's genes sometimes cause a heart defect. The changed genes may come from the parents, or the changes may happen during pregnancy.

Several things may increase the chance that your baby has a congenital heart defect, such as:

  • Your health before and during pregnancy, including: Having diabetes before pregnancy or developing it in the first 3 months of pregnancy (diabetes that develops later in pregnancy isn't a major risk for heart defects). Carefully controlling your blood glucose, also called blood sugar, before and during pregnancy can lower your baby's risk of congenital heart defects.
  • Having phenylketonuria (PKU), a rare inherited disorder that affects how the body uses a protein in foods. If you have PKU, eating a low-protein diet before getting pregnant can lower your baby's risk of having a congenital heart defect.
  • Having rubella (German measles) during pregnancy.
  • Smoking or secondhand smoke (breathing smoke from another smoker).
  • Certain medicines, such as angiotensin-converting (ACE) inhibitors for high blood pressure and retinoic acids for acne. If you're pregnant or plan to get pregnant, talk with your health care provider about all the medicines you take.

Congenital heart defects don't cause pain. The signs and symptoms are different, depending on the type and number of defects and how serious they are.

Common signs and symptoms of congenital heart defects include:

  • Cyanosis - a bluish color to the skin, lips, and fingernails. It happens when there isn't enough oxygen in the blood.
  • Fatigue - your baby may be unusually sleepy and may become very tired during feedings.
  • Poor blood flow.
  • Fast or difficult breathing.
  • Heart murmur - an unusual sound between heartbeats.

Congenital heart defects don't always cause other problems. If they do, which problems you have would depend on the type and number of defects and how serious the defects are.

Children with congenital heart defects are more likely to:

  • Be smaller than other children
  • Have problems or delays in mental, and emotional growth, and behavior, such as: Speech and language problems
  • Attention deficit hyperactivity disorder (ADHD)

People with congenital heart defects may develop other health conditions, including:

  • Endocarditis - an infection of lining of the heart and valves
  • Arrhythmia - a problem with the rate or rhythm of your heartbeat
  • Heart failure - when your heart can't pump enough blood to the body
  • Pulmonary hypertension - high blood pressure in your lungs
  • Kidney and liver disease
  • Before a baby is born, your provider may use ultrasound pictures of the fetus's heart to look for heart defects. This is called a fetal echocardiogram. It's done between weeks 18 and 22 of pregnancy.
  • During the first few days after birth, all newborns are checked for congenital heart defects. A pulse oximeter is clipped to your baby's hands or feet to measure blood oxygen. If it shows low levels of blood oxygen, more tests will be needed to find out if your baby has a heart defect.
  • To diagnose congenital heart defects in babies, children, and adults, a provider may use many tools, including: A physical exam.
  • Certain heart tests to see how the heart is working.
  • Genetic testing to see if certain gene problems caused the defect.

Treatment depends on the type of congenital heart defect and how serious it is. Possible treatments include:

  • Cardiac catheterization to repair simple defects, such as a small hole in the inside wall of the heart. A catheterization uses a thin tube guided through a vein and into the heart.
  • Heart surgery may be needed to: Repair defects in the heart and blood vessels.
  • Repair or replace a heart valve.
  • Place a device in the chest to help the heart pump blood.
  • Do a heart transplant

All children and adults who have congenital heart defects need regular follow-up care from a cardiologist (a doctor who specializes in heart diseases) throughout their life, even if their defect was repaired.

Some people may need several heart surgeries or catheterizations over the years. They may also need to take medicines to help their hearts work as well as possible.

It sits within Blood, Heart and Circulation and Genetics/Birth Defects.

The lead U.S. institute for this subject is the National Heart, Lung, and Blood Institute.

When to speak to someone. Reading about a topic cannot tell you whether it applies to you. Speak to a doctor or pharmacist if symptoms are severe, sudden, getting worse, or simply not going away — and seek emergency care immediately for chest pain, breathing difficulty, sudden weakness or confusion, or a serious allergic reaction.

Research on Congenital Heart Defects

2,192 studies areregistered for this condition on ClinicalTrials.gov, the U.S. National Library of Medicine's public registry. A selection is below — the links go straight to the registry entry, not to a summary of ours.

What a registered study does and does not mean. Registration means a study exists and has been declared publicly. It says nothing about whether the treatment being tested works, is safe, or is available to you. Many studies find no benefit — that is what research is for. Never seek out an experimental treatment on the strength of a registry entry alone.

Research currently under way

Research already completed

Study data from ClinicalTrials.gov, a service of the U.S. National Library of Medicine. Retrieved 2026-07-30. Registry entries are supplied by study sponsors and investigators; ClinicalTrials.gov does not verify their scientific validity. PocketsInfo is not affiliated with, and not endorsed by, the NLM or the NIH.

Where to read more

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Medical subject headings

Clinicians and researchers index this subject under Heart Defects, Congenital. These are the terms to use when searching medical literature.

This page is built from the MedlinePlus health topic record for Congenital Heart Defects, a service of the U.S. National Library of Medicine (NLM), National Institutes of Health. Information is from MedlinePlus.gov. PocketsInfo is not affiliated with, and is not endorsed by, the NLM or the NIH. Retrieved 30 July 2026.