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

Congenital heart disease may initially be suspected during a routine ultrasound scan of the baby in the womb. Specialist ultrasound, called foetal echocardiography, will then be carried out at around 18 to 22 weeks of the pregnancy to try to confirm the exact diagnosis.

This may also be undertaken if there's a family history of congenital heart disease or where there's an increased risk. Echocardiography is a type of ultrasound scan, where high-frequency sound waves are used to create an image of the heart.

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

Read more about ultrasound scans during pregnancy.

It's sometimes possible to diagnose a baby with congenital heart disease shortly after birth if some of the characteristic signs or symptoms of congenital heart disease, such as a blue tinge to the skin or lips (cyanosis), are present.

Your baby's heart will be checked as part of the newborn physical examination. The examination involves observing your baby, feeling their pulse, and listening to their heart with a stethoscope. Heart murmurs are sometimes picked up.

However, some defects don't cause any noticeable symptoms for several months or even years. You should see your GP if you or your child shows signs of the condition. Further testing can usually help to confirm or rule out a diagnosis.

Further tests may be used to diagnose congenital heart disease.

Echocardiography

An echocardiogram is often used to check the inside of the heart. Heart problems that were missed during foetal echocardiography can sometimes be detected as a child develops.

Electrocardiogram

An electrocardiogram (ECG) is a test that measures the heart's electrical activity. Sticky sensors called electrodes are attached to the arms, leg and chest. These are connected by wires to an ECG recording machine. The machine displays the electrical signals produced by the heart and shows how well it's beating.

Chest X-ray

A chest X-ray of the heart and lungs can be used to check whether there's 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 the procedure, a small, flexible tube called a catheter is inserted into a blood vessel, usually through an artery and/or vein in the groin, neck or arm. The catheter is moved into the heart, guided by X-rays or sometimes an MRI scanner, and allows pressure measurements in different parts of the heart or lungs to be taken.

A coloured dye that shows up on X-rays can also be injected into the catheter. This is called an angiogram. The dye can be studied as it moves through the heart, allowing the shape and function of each heart chamber, vessels and the lung to be assessed.

Cardiac catheterisation is painless, because it's carried out under a general anaesthetic or a local anaesthetic.

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

Charities and support groups you may find useful include:

• The Children's Heart Federation – a group of charities 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
• British Heart Foundation – a national charity offering information, support and research into cardiovascular diseases
• Healthtalk.org – a website with a range of stories about children with different types of congenital heart disease, including interviews with their parents
• The Somerville Foundation – a national charity supporting young people and adults born with a heart condition

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

Read about how to care for a disabled child

The specialist nurse at the congenital heart disease department at your hospital can point you in the direction of further information.