Diagnosing congenital heart disease 

In most cases, congenital heart disease is diagnosed during pregnancy. However, a diagnosis may sometimes only be confirmed after the birth.

Diagnosis during pregnancy

Congenital heart disease can be diagnosed during pregnancy with a procedure called foetal echocardiography.

Foetal echocardiography uses an ultrasound scanner to build up a picture of an unborn baby's heart. The procedure should be carried out during routine antenatal examinations, usually some time between week 18 and week 20 of pregnancy.

However, it is not always possible to detect heart defects, particularly mild ones, using foetal echocardiography.

Read more about ultrasound scans during pregnancy.

Diagnosis after the birth

It is sometimes possible to diagnose a baby shortly after birth if it has some of the characteristic symptoms of congenital heart disease, such as a blue tinge to the skin (cyanosis).

However, some defects don't cause any noticeable symptoms for several months or even years.

See symptoms of congenital heart disease for more information about things to look out for in yourself or your child.

See your GP if you or your child shows signs of the condition. Further testing can usually help confirm or disprove a diagnosis.

Further testing

Further tests that may be used to diagnose congenital heart disease are described below.


Echocardiography is a type of ultrasound scan, which means it uses high frequency sound waves to create an image of the heart. 

It may be used to check the inside of the heart. Sometimes, problems with the heart that were missed during foetal echocardiography can be detected as a child develops.


An electrocardiogram is a test that measures the electrical activity of the heart. Electrodes are placed on the skin around the heart and are connected to a computer. The computer analyses the electrical signals produced by the heart to assess how well it is beating.

Chest X-ray

A chest X-ray of the heart and lungs can be used to check whether there is an excess amount of blood in the lungs or whether the heart is larger than normal. Both may be signs of heart disease.

Pulse oximetry

Pulse oximetry is a test that measures the amount of oxygen present in the blood.

The test involves placing a special sensor on the fingertip, ear or toe that sends out light waves. A computer is connected to the sensor and measures how the light waves are absorbed.

Oxygen can affect how the light waves are absorbed, so by analysing the results the computer can quickly determine how much oxygen is present in the blood.

Cardiac catheterisation

Cardiac catheterisation is a useful way of obtaining more information about exactly how the blood is being pumped through the heart.

During this procedure, a small flexible tube called a catheter is inserted into a blood vessel, usually in the groin or arm. The tube is moved up into the heart, guided by X-rays or MRI scanners.

The end of the tube contains a tiny blood pressure monitor, which can be used to take blood pressure readings in different parts of the heart.

A coloured dye that shows up on X-rays can also be injected into the tube. The dye can be studied as it moves through the heart, enabling medical staff to see how well each chamber of the heart is working.

The procedure is painless, as it is performed under a local anaesthetic.

Coping with a diagnosis

Being told that you or your child has a complex and lifelong condition such as congenital heart disease can be a confusing and frightening experience, even if their condition is relatively mild.

It's natural to want to find out as much as possible about congenital heart disease, including the available treatments, and how it can affect your life.

Below is a list of charities and support groups you may find useful:

  • The Children's Heart Federation – a charity dedicated to helping people affected by congenital heart disease
  • The Down's Heart Group – a charity offering support and information on heart conditions associated with Down's syndrome
  • Healthtalkonline.org – a website with a range of stories about children with different types of congenital heart disease, including interviews with their parents

You may also want to find out what help is available for parents who care for children with complex conditions. Find out more about parent caring.

Page last reviewed: 22/04/2013

Next review due: 22/04/2015