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Patent Ductus Arteriosus (PDA)

The ductus arteriosus is a blood vessel that allows blood to bypass a babies’ lungs while they are in the womb.

This is because their lungs are underdeveloped until they start breathing. The ductus arteriosus therefore acts as a ‘safety feature’ and is biologically programmed to shut when babies are born at full-term.

The closure usually happens in the first few days or weeks after birth. If it remains open, it is known as PDA.

PDA means a baby has an additional (and abnormal) source of blood flow to the lungs. As a result, there is extra strain on the left-hand side of the heart, which has to collect and deal with the extra blood.


What causes PDA?

This is a congenital heart defect (present when your child was born). The exact cause isn’t often clear. Most heart problems in children are present from birth due to an anomaly in the way the heart forms during the very early stages of pregnancy.

The reasons for this may be due to a number of factors, such as genetics, environmental factors or infection. The likelihood that a heart problem will have been caused directly by anything you have done during pregnancy or early life is very rare.


What are the signs and symptoms of PDA?

The signs and symptoms will vary depending on the size of the PDA, the age of your child and whether they have any other heart problems.

  • Small ducts (PDA) Your child may not have any symptoms and the PDA may only be picked up at a routine health check where a heart murmur is also detected.  
  • Moderate ducts (PDA) Your child may have symptoms of heart failure, such as breathlessness, poor feeding or impaired growth. They may also be more susceptible to chest infections.
  • Large ducts (PDA) Your child may have signs of severe heart failure, such as breathlessness at rest, failure to thrive and multiple respiratory infections.


How is PDA?

Your child will have an echocardiogram, a non-invasive, high frequency ultrasound scan of the heart. It allows doctors to see the PDA, the aorta and pulmonary blood vessels, how blood is moving through the heart and the impact the blood flow is having on other components of the heart.

Doctors will look to see whether the left ventricle (one of the lower pumping chambers) is dilated, a sign that it is working harder than it should be.


How is PDA treated?

The treatment your child will need will depend on the size of the PDA and any other heart problems they might have.

If the PDA is not affecting blood flow to the heart (and is not audible via stethoscope), it is unlikely to cause your child any health problems in the future.

The first line of treatment in a new born baby is usually with medication to try to close the PDA. If this is not appropriate or does not work, your child will need surgical treatment and we will refer you to Great Ormond Street Hospital for this.


What happens next?

The long-term outlook for PDAs is very good irrespective of the strategy used to close the hole (catheter device closure or cardiac surgery). Further surgical or catheter procedures are not usually required and children lead normal, healthy lives.

Further reading

Read about patent ductus arteriosus on the Children's Heart Federation website 

Understanding your child's heart - patent ductus arteriosus on the British Heart Foundation website