What Is Pulmonary Stenosis in Children?

Medically Reviewed by Dan Brennan, MD on July 24, 2022

Pulmonary stenosis is a condition that affects how much blood makes its way to the lungs. This is often diagnosed at birth and accounts for 8% of all congenital heart disease.

What Is Pulmonary Stenosis?

What is pulmonary stenosis in children? This congenital birth defect in the heart happens if, during the first two months of pregnancy, the pulmonary valve doesn’t develop like it needs to. The pulmonary valve is what hooks the right ventricle up to the pulmonary artery. It should have three leaflets, or flaps, that let blood pass to the pulmonary artery from the right ventricle but not the other way around. Pulmonary stenosis makes it difficult for these flaps to open and for blood to move around like it needs to.

It could be that your child’s flaps are stuck together, the flaps are too thick to open up all the way, the valve is narrower than usual, or something is abnormal about the way areas surrounding the valve developed. This condition can range from minor to extremely severe, depending on how intense the blocked blood flow is. If your child has high blockage, they’ll probably be very sick with obvious symptoms. If your child has low blockage, they might show few to no symptoms. A child with mild pulmonary stenosis, however, can develop worse blockage and more symptoms further down the road.

It’s not common to discover pulmonary stenosis in children before they’re born. This condition usually happens alongside other congenital heart defects. Pulmonary stenosis types include:

  • Valvar pulmonary stenosis, where the flaps are too thick or too narrow
  • Supravalvar pulmonary stenosis, where the pulmonary artery on top of the valve is too narrow
  • Subvalvar, or infundibular, pulmonary stenosis, where the muscles directly underneath the valve is too thick
  • Branch peripheral pulmonic stenosis, where the left pulmonary artery, right pulmonary artery, or both are too narrow

Causes of Pulmonary Stenosis

This heart condition happens because of poor development in the pulmonary valve during the first eight weeks of pregnancy. A number of factors can contribute to this, but usually it happens at random without a clear reason for improper development. It’s possible that pulmonary stenosis, like other congenital heart defects, could be genetic, happen because of a chromosome abnormality, or come about after environmental exposure.

Symptoms of Pulmonary Stenosis

Often, pulmonary stenosis won’t have any signs in new babies or young children. As your child gets older, it’s likely that pulmonary stenosis symptoms will show up. Signs of this condition can include:

Many health conditions share the symptoms of pulmonary stenosis. If you notice anything abnormal about your child or their behavior, consult with their healthcare provider.

Diagnosing Pulmonary Stenosis

When diagnosing pulmonary stenosis, your child’s healthcare provider will want to review the child’s health history and symptoms. The healthcare provider will likely perform a physical exam, listen to your child’s lungs and heart with a stethoscope, and look for other signs of a heart condition. You might have to see a pediatric cardiologist, a specialist for children’s heart issues, who might run a few tests:

  • Chest X-ray
  • Electrocardiogram (ECG)
  • Echocardiogram
  • Cardiac catheterization
  • Pulse oximetry
  • Cardiac MRI

Treating Pulmonary Stenosis

If your child has mild pulmonary stenosis, they probably won’t need treatment. A moderate to severe condition, however, will need to be repaired. If your newborn is extremely sick, they will need to heal before the condition can be fixed. If your newborn’s pulmonary stenosis is life-threatening, they’ll need emergency attention. They’ll receive medicine to keep blood flowing in the lungs until they’re stable enough to receive a procedure. Alternatively, a child with a less severe condition will be able to schedule the repair. Options for pulmonary stenosis treatment include:

  • Valvotomy. A procedure to remove scar tissue from the flaps to allow the valve to open wider.
  • Valvectomy. A procedure to remove the valve and replace it with a patch that lets blood flow properly.
  • Valvuloplasty. A procedure also known as balloon dilation that inserts a balloon into a narrow valve and inflates it to stretch the area.
  • Patch enlargement. A procedure to make narrow areas wider by adding patches to the pulmonary artery or right ventricle.
  • Pulmonary valve replacement. A procedure to replace your child’s valve with a pig or human tissue valve.

Complication of Pulmonary Stenosis

When left untreated, moderate and severe pulmonary stenosis in children can result in complications. Your child’s right ventricle will have to work harder than normal to get blood through the abnormal valve or narrow area. This can cause it to get bigger and be tired from the extra labor. As a result, failing to pump correctly, also known as heart failure, and an abnormal heart rhythm, also known as arrhythmia, can affect your child.

Overworking the right ventricle can also cause pressure buildup in the right atrium, causing veins to pump blood back to the right side of the heart. When this happens, swelling and fluid retention are common side effects.

When To Call a Healthcare Provider for Pulmonary Stenosis

If you suspect your child has pulmonary stenosis or if they’ve been diagnosed but the condition hasn’t been corrected, keep in close contact with their healthcare provider. Your child should have frequent check-ups with a pediatric cardiologist for their whole childhood. Your child might need to be on medication or not take part in heavy physical activity. Once they reach adulthood, your child should still meet with a cardiologist. With time, blood can start  leaking through the underdeveloped valve, called pulmonic insufficiency or pulmonary regulation.

If you notice any of the following symptoms, reach out to your child’s healthcare provider immediately:

  • Trouble breathing
  • Heart beating quickly
  • Fatigue
  • Swollen feet, ankles, legs, stomach, or face

Show Sources


Children’s Hospital of Philadelphia: “Pulmonary Stenosis.”

Children’s National: “Pediatric Pulmonary Stenosis.”

Stanford Children’s Health: “Pulmonary Stenosis in Children.”

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