Pulmonary Stenosis


Pulmonary stenosis is a congenital heart defect in which the pulmonary valve is underdeveloped and/or thickened or abnormal and does not open normally. The pulmonary valve is the opening that allows blood to flow from the right side of the heart to the lungs to collect oxygen.

When the valve is abnormal, less blood can flow across it to the lungs. In addition, the lower pumping chamber on the right side of the heart (right ventricle) has to work harder to pump enough blood through the valve to the lungs.

Pulmonary stenosis can range from mild to severe. It can also worsen over time.

In babies with severe blockage, the heart may weaken over time. If untreated, heart failure can occur.

Pulmonary stenosis may be an isolated condition or it can occur as part of complex congenital heart conditions involving multiples defects, such as tetralogy of Fallot.

What happens in pulmonary stenosis?

The pulmonary valve is located between the right ventricle (lower, pumping chamber) and the pulmonary artery, which carries blood from the heart to the lungs.

The one-way valve is made up of three flaps or “leaflets” that open when the right ventricle contracts, allowing oxygen-poor blood to be pumped out to the lungs. The flaps close when the ventricle relaxes, preventing the blood from leaking back into the heart.

In babies with pulmonary stenosis, the pulmonary valve does not form normally. The valve leaflets may be small, underdeveloped, thickened and tethered, preventing the valve from opening completely and obstructing blood flow to the lungs.

As a result, oxygen-poor blood cannot flow out of the right side of the heart to the lungs as it should. Pressure builds up in the baby’s right ventricle, which must work harder to push blood through the smaller valve opening. In pulmonary stenosis, the right ventricle may be thickened and underdeveloped. In addition, the valve leading into the right ventricle (known as the tricuspid valve) may be underdeveloped and not open normally (known as tricuspid stenosis) and in many cases may leak (known as tricuspid regurgitation).

Symptoms of Pulmonary Stenosis

Symptoms of pulmonary stenosis can include:

  • Cyanosis, a blue tint to the baby’s skin, lips or nails indicating a lack of oxygen in the blood
  • Irregular heartbeat (arrhythmia)
  • Breathing difficulties
  • Fatigue
  • Fluid retention
  • Heart failure, in severe cases where the ventricle becomes too weak to pump effectively


Pulmonary stenosis is a congenital defect, meaning it is present at birth. The condition occurs when the heart doesn’t form properly during fetal development.

The cause is unknown. It can occur in certain genetic disorders (such as Noonan Syndrome).


Before birth

Pulmonary stenosis may be diagnosed during a routine fetal echocardiogram (ultrasound of the fetal heart). A diagnosis during pregnancy enables your family and your healthcare team to plan ahead for the specialized treatment and cardiac expertise your baby may need at birth, optimizing outcomes. Typically the more severe the condition, the earlier the diagnosis.

After birth

If the condition is not detected during pregnancy, it may be suspected after birth if a heart murmur is heard during a physical exam. Additional symptoms may include breathing difficulties, fatigue, a rapid heartbeat, swelling, and a bluish tint to the skin or lips indicating a lack of oxygen in the baby’s blood. Your child will be referred to a pediatric cardiologist for a consultation and additional testing.

Specialized Evaluation and Prenatal Care

If pulmonary stenosis is diagnosed during pregnancy, prompt referral to a fetal cardiac center is important for further evaluation and to ensure proper treatment.

At Texas Children’s Fetal Center, we arrange for you to visit as quickly as possible for a comprehensive assessment by a team of specialists experienced in working together to diagnose and treat congenital heart defects. Your healthcare team will include maternal-fetal medicine physicians (OB/GYNs specializing in high-risk pregnancies), fetal and pediatric cardiologists, fetal imaging experts, genetic counselors, congenital heart surgeons and neonatologists.

Additional testing may include:

Our specialists will then meet with you about the results, provide treatment recommendations, and answer any questions your family has, to help you make the most informed decisions regarding your baby’s care and treatment.

During pregnancy, mother and baby will be closely monitored for early detection of complications or signs the condition is worsening, including fetal non-immune hydrops (fluid accumulation in multiple areas of the baby’s body) and fetal heart failure, requiring early delivery.


For the best possible outcomes, delivery should take place at a center with the highest quality congenital heart program, ensuring the expertise and resources required to treat pulmonary stenosis at birth, including an advanced neonatal intensive care unit (NICU) and dedicated cardiac intensive care unit (CICU).

Delivery and postnatal care should be carefully planned and coordinated. Our Fetal Center team works closely with Texas Children’s Heart Center, seamlessly transitioning your baby’s care at delivery to this national leader in pediatric cardiology and heart surgery. Here, the heart specialists treating your newborn have been an integral part of their care team since before birth.

Following delivery at Texas Children’s Pavilion for Women, newborns are transferred to Texas Children’s level IV NICU, the highest level of care available for premature and critically ill newborns, or Texas Children’s specialized CICU

Treatment After Birth

Treatment depends on the location and severity of the pulmonary valve stenosis, your child’s age, symptoms, overall health, and any other defects present. In cases of mild pulmonary stenosis, patients often do not have symptoms and treatment is usually not required, only regular monitoring by a cardiologist experienced in congenital heart defects.

In more serious cases, treatment strategies include:

  • Medication to treat the baby’s symptoms. In the case of “critical” or severe pulmonary stenosis, a medication called prostaglandin (PGE) may be required following birth to keep open an artery (known as a ductus arteriosus), ensuring adequate blood flow to the lungs until the baby can undergo further treatment.
  • Cardiac catheterization to perform a balloon valvuloplasty or ductal stenting. In balloon valvuloplasty, a thin, flexible tube (catheter) with a deflated balloon on the end is inserted into an artery in the groin and into the heart. The balloon-tipped catheter is advanced across the pulmonary valve and inflated to enlarge the opening. In some cases, a special catheter with a stent (a tiny wire mesh tube used to prop open a vessel) may also be placed in an artery (known as a ductus arteriosus) to provide additional blood flow to the lungs and give the right side of the heart time to improve in size and function.
  • Heart surgery to open, repair, remove or replace the pulmonary valve, improving blood flow from the right ventricle into the pulmonary artery. In some cases, the surgeon will perform a valvotomy in which he makes a small incision or dilates the pulmonary valve to enlarge the opening. In other cases, the surgeon may perform a valvectomy where he removes the pulmonary valve and replaces it with a new valve. The surgeon can also use patch material to enlarge the area above the valve and may remove some muscle below the valve.  

Postnatal Care Team

Depending on the severity of his or her condition, your baby’s postnatal care team may include:

Babies born with pulmonary stenosis require lifelong care and monitoring by a cardiologist experienced in congenital heart defects. In some cases, the valve may narrow again and additional procedures may be needed.

At Texas Children’s Heart Center, our pediatric cardiologists follow your child through adolescence, seamlessly transitioning their care at adulthood to a cardiologist who specializes in the unique needs and treatment of adults with congenital heart defects

Why Texas Children’s Fetal Center?

  • A single location for expert maternal, fetal and pediatric care. Texas Children’s Hospital offers mothers and babies the specialized care required for the diagnosis and treatment of congenital heart conditions all in one location, for highly coordinated care and treatment planning.
  • A skilled, experienced team with proven outcomes. We have a dedicated team of maternal-fetal medicine specialists, fetal imaging experts, fetal and pediatric cardiologists, congenital heart surgeons, neonatologists and others who work in concert to care for you and your baby every step of the way, using proven protocols we’ve developed over the years. With their combined expertise and unified approach, this team offers the best possible care for pulmonary stenosis.
  • We care for your child’s cardiac needs at every stage of life, from fetus to adulthood. Our comprehensive approach starts with your first prenatal visit and continues through delivery, postnatal care, childhood and adulthood, thanks to one of the nation’s leading teams of fetal, pediatric and adult congenital heart specialists.

Texas Children’s – #1 in the Nation for Pediatric Cardiology and Heart Surgery

Our Fetal Cardiology Program is a collaboration between Texas Children’s Fetal Center and Texas Children’s Heart Center, ranked #1 in the nation for pediatric cardiology and heart surgery by U.S. News & World Report for consecutive years, with outcomes among the best in the country.

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Additional Resources

Research and Clinical Trials

Texas Children’s, together with our partner institution Baylor College of Medicine, constantly strives to seek new and better treatments for babies with congenital heart defects.

Learn more about our fetal cardiology research.

For additional information, please contact the Cardiovascular Clinical Research Core at 832-826-2064 or email sandrea@texaschildrens.org.

For more information or to schedule an appointment,

call Texas Children’s Fetal Center at 832-822-2229 or 1-877-FetalRx (338-2579) toll-free.

Our phones are answered 24/7. Immediate appointments are often available.