• Congenital heart disease occurs when a baby’s heart or blood vessels develop in abnormal ways in the womb.
• Some of the symptoms of congenital heart disease include blue blotches of skin at birth, abnormal heart murmurs, and delays in developmental milestones.
• There is no cure for congenital heart disease, and the risks of living with the condition can range from fairly innocuous to extremely dangerous.
• This article was reviewed by John Osborne, MD, PhD and the Director of Cardiology for Dallas-based State of the Heart Cardiology.
• Visit Insider’s homepage for more stories.

Congenital heart disease refers to heart defects present at birth. According to the Centres for Disease Control and Prevention, about 1% of US infants, or about 40,000 children each year, are born with some type of heart defect.

There are at least 18 distinct types of congenital heart defects, and they can affect a baby’s life in different ways. Here’s what you need to know.

Congenital heart disease happens at birth

Congenital heart defects occur when a baby’s heart or blood vessels develop abnormally before birth. Some of the most common congenital heart defects include:

• Ventricular septal defect, the most common congenital heart defect, is when a hole forms between the ventricles in utero. The condition causes more blood to be pumped through the heart and lungs, making those organs work harder. If not repaired, it increases the likelihood of high blood pressure in the lungs, heart failure, arrhythmia, and stroke.
• Patent ductus arteriosus occurs due to a failed closing connection amid the heart’s two major arteries. The defect leads to a hole which can leak blood when it shouldn’t. It’s a common condition, according to the National Institutes of Health (NIH), and the hole can often close on its own over time.
• Tetralogy of Fallot (TOF) is a common, complex heart defect, according to the NIH. It involves four main heart problems: interference from the heart to the lungs, a gap between the heart’s lower chambers, the aorta lying over the heart’s gap in the lower chambers, and excessively broadened muscles surrounding the heart’s right lower chamber.

Common signs of congenital heart defects

Sometimes specific heart defects show clear signs. Samuel Dudley, MD, a cardiologist at the University of Minnesota, says that TOF can cause blood to be improperly oxygenated. Unoxygenated blood looks blue, and about 9% to 14% of babies with congenital heart defects are born with blue blotches of skin, a condition known as blue baby syndrome.

Common indicators also apply to many types of congenital heart defects. For example, the heart may elicit a “whoosh” sound under a stethoscope, which indicates a heart murmur, says Dudley. Murmurs happen when blood travels in a different pathway in the heart, forgoing the “lub-dub” noise of a healthy heart, and can be present at birth.

Other signs are less obvious. Babies may have trouble breathing, difficulty eating, stunted growth, and delays in developmental milestones from any of the 18 types of congenital heart defects.

The causes of congenital heart defects

An embryo’s heart starts out as two tubes that merge to form a single tube. The tube then twists to form four chambers: the right and left atriums and ventricles. Dudley says errors in this process cause congenital heart defects, though it’s not always clear how.

According to the CDC, at least 15% of congenital heart defects are genetic. Having a parent with a congenital heart defect triples the likelihood that the child will have it.

Maternal factors also have an impact. Consuming alcohol, taking medications like thalidomide and lithium, and smoking cigarettes within the first trimester of pregnancy can increase the risk of heart malformations in the child. Viral infections like rubella can also contribute to congenital heart defects.

Finally, the National Down Syndrome Society (NDSS) reports that nearly half of all children with Down Syndrome have a congenital heart defect. The most common defects include holes in the heart as well as a scenario where the arteries between the lungs and heart fail to close after birth.

That’s why the NDSS recommends children with Down Syndrome should get an echocardiogram – a diagnostic ultrasound – within the first three months of life and have surgery to correct any issues.

Congenital heart defects may or may not impact a child’s life

There are no cures for congenital heart defects. When it comes to determining how dangerous they are, Dudley says that congenital heart defects occur on a spectrum.

On one end are the defects that aren’t very dangerous, where a person can live normally. These include small holes in the heart, as with atrial septal defects, that don’t cause symptoms and may close over time.

On the other side are critical defects that must be dealt with immediately, as with single ventricle defects, where the baby could die within the first month of life. Of all babies born with a heart defect, 25% will have a critical defect that requires heart surgery within their first year of life, according to the CDC.

A doctor must decide if a congenital heart defect is dangerous enough to require intervention immediately, or if the treatment can wait until the child is older and more developed. Depending on the severity, a child might need medication such as ibuprofen to expedite the closing of holes in the heart or a more serious heart procedure like surgery or catheterization.

Those with congenital heart defects can live a normal life, though Dudley says they might not be able to exercise as vigorously as those born with healthy hearts.

There are also other risks. A 2016 study also found that those with congenital heart defects were 11 times more likely to have ischemic stroke (at a median age of about 23 years old) than those without. They might also have poor nutrition and developmental growth, since the heart has to use more energy to pump blood throughout your body.

If you’re pregnant, having a congenital heart defect is a common cause of heart problems and complications for the pregnancy. So you are especially advised to talk to a doctor about how the condition can affect both you and the baby.

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