Patent ductus arteriosus (PDA): symptoms, diagnosis and treatment

A PDA does not look the same in every baby. The Sussex neonatal leaflet explains that the effects on a baby may include extra effort to breathe, fluid in the lungs because additional blood is being sent there, and extra work for the heart. Nurses and doctors on a neonatal unit usually pick these up through monitoring rather than parents noticing something at the cot side.

• A faster breathing rate or more effort to breathe.

• Needing more oxygen to keep blood oxygen levels steady, or drops in the measured oxygen level (desaturations).

• Apnoea, meaning not breathing for more than about 10 to 20 seconds.

• A heart murmur, which a doctor hears with a stethoscope, and a faster heart rate.

• A baby who is quieter than usual, does not like being handled as usual or is not gaining weight, which are the ways nurses may describe it to parents.

Before birth, a baby’s lungs are not used for breathing, so most blood does not need to travel through them. The ductus arteriosus is a short vessel that diverts blood away from the lungs by connecting the pulmonary artery (the main artery to the lungs) to the aorta (the main artery to the body). This is a normal and useful part of development in the womb.

After birth the lungs take over. The duct normally begins to close straight away and, in full-term babies, University Hospitals Sussex NHS Foundation Trust says it is usually completely closed within a couple of days. “Patent” simply means open. When the duct stays open, blood that should travel around the body can flow back into the lungs, which increases blood flow to the lungs and gives the heart more work to do.

The sources used for this guide are neonatal unit and NHS information, so they concentrate on PDA in newborn babies, particularly those born early. The NHS describes the wider group of heart conditions people are born with as congenital heart disease, and a PDA sits within that group.

On a neonatal unit, the doctor examines the baby, listens to the heart, talks to the nurses, reviews observations such as heart rate, breathing rate and blood pressure, checks blood results and arranges a chest X-ray. If a PDA is suspected, an echocardiogram can confirm it. The Sussex leaflet likens this scan to the ultrasound used in pregnancy and says it shows how blood is flowing through the heart.

The NHS adds that congenital heart disease is screened for at the 20-week pregnancy scan, but that this scan cannot find all conditions, so some are not picked up until later. Other tests for heart conditions in children include pulse oximetry, which measures how much oxygen is in the blood, an electrocardiogram, and further scans.

Treatment depends on how the baby is affected. Initial management described by the Sussex trust is supportive: giving smaller feeds to reduce the extra fluid in the lungs, offering breathing support such as oxygen through small nasal prongs, CPAP or Optiflow, and sometimes diuretics, which help the body remove fluid by producing more urine.

Great Ormond Street Hospital says that to try to close the connection a baby may be given a non-steroidal anti-inflammatory medicine such as ibuprofen, and that sometimes medicine is unsuccessful or not appropriate and a closure procedure is needed. It describes a catheter procedure in which a device is placed in the duct through a vein at the top of the leg, with the position checked by echocardiography and X-ray. The risks it lists include bleeding, infection, damage to blood vessels or heart valves, and the device moving, and it notes a very rare risk of death.

Babies with a PDA that is being treated are usually in hospital and under constant observation, so the team will act on changes. For any child, though, the NHS gives clear guidance on heart-related symptoms. It says to call 999 if a child’s lips, tongue, face or skin suddenly turn blue or grey, if they have difficulty breathing, or if a child is limp, floppy or not responding as they normally do.

For symptoms that are less sudden, the NHS advises asking for an urgent GP appointment or getting help from NHS 111, and says to call 111 for advice about a child under 5 years old. Difficulty feeding and slow weight gain are among the symptoms the NHS lists for congenital heart disease in babies and children, so they are worth raising with a GP or health visitor.

The duct stays open far more often in babies born early. The Sussex leaflet explains that it may remain open in premature babies and that a PDA is the name for this. The sources read for this guide do not give a detailed breakdown of every possible cause, and it would not be right to guess beyond them.

More broadly, the NHS says congenital heart disease develops while the heart is still being formed in the womb. Sometimes an altered gene passed on from a parent is responsible, but often there is no clear reason. Factors that can make a baby more likely to have a heart condition include obesity in pregnancy, smoking or second-hand smoke, gestational diabetes and infections such as rubella.

The Sussex leaflet says it may take a while for a baby to show complete improvement after surgery, because the body has to adjust to the duct being closed and the baby has also had an operation and a journey between hospitals. It says most babies do well following the operation.

Follow-up is usually through the neonatal outpatient team to monitor growth and development, and the leaflet states there is no need for separate cardiac follow-up appointments in that service. Practice can differ between hospitals, so your own team can tell you what applies to your baby. The British Heart Foundation is named by both the leaflet and the NHS as a source of support for families.

A PDA in a newborn is managed within NHS neonatal and paediatric cardiology services, which are free at the point of use. If your child is diagnosed with congenital heart disease, the NHS says you will be referred to a specialist team at an NHS hospital, and some children need only regular check-ups.

Some families also seek a private paediatric cardiology opinion for reassurance or a second view. Private care generally involves the same type of tests, such as an echocardiogram, with differences mainly in waiting times and choice of clinician. For a baby who is already on a neonatal unit, the practical question is usually about additional opinions rather than a choice of provider, and the neonatal team can advise on how a second opinion could be arranged.