Patient Information

Heart murmurs (newborns)


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This is for anyone who is looking after a baby or child with a heart murmur.

What is a heart murmur?

A heart murmur is an added sound heard when listening to your baby’s chest. It is usually a whoosh noise which occurs when blood is passing through a smaller gap in the heart. When your baby is in the womb, their circulation is different to how it is after they are born. The transition to normal circulation takes time, and a murmur can often be heard when this transition is happening.

What causes a heart murmur?

Many babies and younger children have heart murmurs and this does not mean they have underlying heart problems. The murmur may become more obvious when your child is unwell, because their heart is beating faster. We refer to this as an innocent murmur.

A small number of children with a murmur have a problem with the blood flow in their heart. It can be caused by a structural defect between the chambers of the heart or by narrowing/leaking heart valves. This may get better on its own or it may need treatment.

What further tests are needed?

cute baby

If we find a murmur, we may do some initial tests to check that your baby is well. These might include an ECG (an electrical tracing of the heart), or tests of blood pressure and oxygen saturation. If everything is normal, your baby can usually be discharged home. We will reassess your baby at their 6 to 8 week baby check, to see if their murmur is still present. Often the murmur has gone away by the 6 to 8 week check.

If the doctor can still hear a murmur, we may need to make some images of their heart. This is called an echocardiogram. It is an ultrasound scan which enables the doctor or test technician to see the structure of your baby’s heart and their blood flow. It may show if there are any defects or abnormal blood flows within the heart.

Does my baby’s murmur need treatment?

Most murmurs resolve on their own and don’t need treatment. Sometimes follow up appointments are needed so that your child is regularly reviewed to reassess the murmur.

If there is a heart defect or abnormal blood flow, your baby may require treatment with medication or surgery. A heart specialist will discuss this with you if needed.

What do I look out for when I take my baby home?

Most babies with heart murmurs are healthy. Make an appointment with your GP or other healthcare professional if your baby becomes unwell or develops one or more of the following:

  • breathless/sweaty whilst feeding
  • feeding difficulty and poor weight gain.

When to take your baby to the Emergency Department (A&E)

Take your baby to the Emergency Department (A&E) if they have:

  • blue discoloration of skin/lips
  • difficulty with breathing
  • mottled skin.

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Heart murmurs (newborns) - Kingston Hospital Download PDF


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