Patent ductus arteriosus (PDA) is a congenital heart defect that develops soon after birth. The blood flow through the newborn's heart is impaired when a small hole between the artery carrying blood to the body and the artery carrying blood to the lungs does not close as it should.
This congenital heart defect is common in premature infants but rare in infants born at term.
As a baby develops in the womb before birth, blood does not need to go to the lungs to receive oxygen. Instead, the baby receives oxygen through the umbilical cord and the mother's placenta. In addition, a hole between the aorta (the blood vessel carrying blood to the body) and the pulmonary artery (the blood vessel carrying blood to the lungs) allows blood to skip the lungs for the most part and go almost exclusively to the body. This hole is the ductus arteriosus, the passage between the arteries.
After the baby is born, this hole closes to allow blood to flow to the lungs and begin picking up oxygen. When the baby starts to breathe air for the first time, pressure changes in the lungs, and the blood vessels allow the blood to begin flowing into the lungs. The hole between the two arteries also begins to close due to these blood pressure changes. Generally, the hole is functionally closed by about 12 to 24 hours of age in healthy, full-term newborns and permanently closed within 2 to 3 weeks.
When the ductus arteriosus does not close as it should, it may leave a hole that is three to five millimeters in diameter between the aorta and the pulmonary arteries. As a result, blood that should be going to the body can flow into the lungs. This extra blood can cause too much pressure in the lungs.
A small PDA may not cause a problem, but larger ones can cause various problems.
Most of the time, doctors do not know exactly why a child develops PDA, but there are a few factors that seem to affect PDA development:
Premature infants are much more likely to develop PDA. Some studies have suggested that about 65% of infants born before the 28th week of pregnancy will develop PDA. This condition is rare in a full-term infant.
Girls develop them twice as often as boys.
Some genetic conditions are also associated with PDA development.
They frequently occur with other congenital heart defects.
The size of the PDA will determine the symptoms.
Your infant may not have any symptoms if they have a small opening. But if the hole is larger, your baby may develop signs such as:
- Poor weight gain and growth
- Tiring quickly while feeding
- Sweating during feeding
- Frequent lung infections
- Hard or fast breathing
- Low blood pressure
- Shortness of breath
- Fast heart rate
- Heart murmur
Since the exact cause of PDA is unknown, it is difficult to say precisely what may increase an infant's chances of developing the condition. However, some factors appear frequently with PDA.
Conditions found in the mother during pregnancy that may cause PDA in the infant include:
- Certain infections, such as rubella
- Taking certain medications, such as calcium channel blockers
- Cocaine use
- Magnesium exposure
Conditions found in the infant that may result in PDA include:
- Other congenital heart defects
- Certain genetic conditions
- Family history of congenital heart defects
- Fetal distress before birth
- Infections in the infant during pregnancy or right after birth
- Respiratory distress syndrome
- Birth at high altitudes
- Certain medications
Doctors may diagnose your infant with PDA very soon after birth. While they examine your child, they may notice a heart murmur, lung congestion, rapid heart rate, or other signs. If they see something concerning, they may run tests such as an echocardiography or an ECG.
Mild PDAs may not need treatment. The hole will often close without treatment within a few months.
In other situations, your baby may need medicine to help close the hole, such as anti-inflammatories or diuretics.
More severe cases may need procedural interventions. For example, PDA can sometimes be closed during a heart catheterization or may require surgery.
After PDA repair, most infants will live a normal lifespan.
However, if left untreated, complications can arise, such as:
- Heart failure
- Heart infections
- Fluid in the lungs
- High blood pressure in the lungs
- Bleeding in the lungs
- Digestive tract infections
- Bleeding in the brain
- Congestive heart failure
- Kidney failure
- Persistent respiratory distress
- Eisenmenger syndrome
- Premature death
If the PDA is small or has been closed by a medical procedure and is the only health concern, your child may not have any activity restrictions. They may need to see a pediatric cardiologist occasionally to follow up, especially if the hole was closed during catheterization or surgery. They will not usually need medication or additional procedures.
In rare cases, a second surgery may be necessary if the hole opens again.
PDA is a hole between the aorta and the pulmonary artery that does not close properly after birth. As a result, the pressure changes in the heart and blood vessels may cause problems in the heart and lungs.
Usually, the hole will close on its own soon after birth. However, your pediatrician may recommend medicine or a medical procedure to close the hole if it does not close on its own. In addition, you may need to see a cardiologist regularly to monitor your PDA.
Most people with a small PDA or a repaired PDA don't need any medication or activity restrictions. However, your doctor may recommend exercise restrictions if you develop high blood pressure in the lungs due to PDA.
Talk to your doctor if you have PDA and are pregnant or plan to become pregnant. Pregnancy with PDA is usually low risk, but you may have some difficulty if you have high blood pressure in your lungs.
Talk to your doctor if you or your child has any symptoms of PDA.
Gillam-Krakauer, M., et al. (2021). Patent Ductus Arteriosus - StatPearls - NCBI Bookshelf (nih.gov)
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