Patent ductus arteriosus (PDA) is the persistence of an opening that allows the blood to skip circulating through the lungs after a baby is born. This is a developmental abnormality that usually closes shortly after birth.

PDA is more common in premature infants.

A small PDA typically does not cause symptoms, but a larger PDA forces the lungs and heart to work harder, which can cause blood vessel damage. If a PDA does not close on its own, an infant may need surgery.

However, in most cases, medication alone can close a PDA.

Read more to learn more about the causes, symptoms, treatment, and diagnosis of PDA.

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When a fetus is in the womb, blood does not need to travel through the lungs. The ductus arteriosus is a hole in the aorta that allows the blood to bypass the lungs. This is a typical part of development, and all infants are born with this hole.

About 12–24 hours after birth, the hole starts to close. It will close completely in a few weeks.

In some cases, the hole does not close, which can make the lungs and heart work excessively hard. There may be high blood pressure in the arteries of the lungs.

This can cause permanent damage and may also increase the risk of long-term complications and death in premature infants.

It is important to note that most infants with PDA are premature and have low birth weights. The condition is rare in otherwise healthy premature infants.

PDA is typical in developing fetuses, and all infants are born with a PDA.

At birth, a baby takes its first breath, filling the lungs with air for the first time. The tension of oxygen and decreased blood flow through the PDA force it to start closing.

However, in premature infants, breathing difficulties and underdeveloped lungs may delay or prevent the closure of a PDA. Up to 80% of very premature infants still have a PDA at 3 days old.

Some other conditions may also increase the risk of PDA. They include:

A small PDA may cause no symptoms at all.

However, a larger PDA can cause several symptoms, including:

A doctor may suspect PDA or other heart disorders in a very premature infant.

When listening to the heart with a stethoscope, they may hear a heart murmur and assume they have the condition. They can then order a chest X-ray and EKG.

Doctors usually recommend an EKG with color flow and Doppler studies to diagnose PDA. This makes it easier to see blood flow in the heart and lungs. These tests can also determine the size of the hole.

Several days after giving an infant medication to close the PDA, a doctor may repeat these tests to check that it has closed.

Treatment depends on the size of the PDA and if it causes symptoms.

Symptomatic PDAs increase the risk of other complications, so doctors usually prescribe medication to close them. Some medication options include:

  • indomethacin
  • ibuprofen (Advil)
  • acetaminophen (Tylenol)

About 80–90% of PDAs in infants close with medication.

If medication does not work and the PDA still causes symptoms, surgery may be necessary. These procedures pose several risks, especially in premature babies, so parents or caregivers should discuss the risk and benefits with a doctor. However, the risks of untreated PDA generally outweigh the risks of surgery.

The outlook for an infant with PDA depends on many factors. These include:

  • the size of the PDA
  • the infant’s age
  • whether the PDA responds to medication

If PDA is an isolated issue and the infant does not have other health concerns, the prognosis is good.

A PDA does not typically close on its own if it presents when an infant leaves the hospital. However, in those weighing more than 1 kilogram (kg) at birth, PDA usually closes before then.

Medication can close most PDAs, but if it is ineffective, a doctor may recommend surgery.

A 2021 study followed preterm infants receiving care in a neonatal intensive care unit and evaluated their PDAs and outcomes. All babies were born before 32 weeks at less than 1.5 kg.

Researchers found that among infants with a hemodynamically significant PDA (hsPDA) — a PDA significant enough to cause symptoms — the mortality rate was 10.6%. In premature babies without a hsPDA, the mortality rate was 3.6%.

The analysis found that low birth weight and early gestational age, not hsPDA, were risk factors for mortality.

All infants are born with a PDA — an opening that allows the blood to skip circulating through the lungs — but it typically closes on its own. However, if it does not, a doctor may recommend medication or further treatment.

Parents or caregivers of infants with PDA should consult a cardiologist to weigh the risks and benefits of various treatment options. Without treatment, serious PDAs can increase the risk of death as a person gets older.