Children and adults with congenital heart disease are at an increased risk of developing further problems.

Many children with more serious congenital heart disease experience delays in their development. For example, they may take longer to start walking or talking. They may also have lifelong problems with physical co-ordination.

Some children with congenital heart disease also have learning difficulties. These are thought to be caused by a poor oxygen supply during early life, which affects the development of the brain.

Learning difficulties can include:

• impaired memory
• problems expressing themselves using language
• problems understanding the language of others
• low attention span and difficulty concentrating
• poor planning abilities
• poor impulse control – acting rashly without thinking about the possible consequences

These can lead to problems with social interaction and behaviour in later life.

The risk of developing respiratory tract infections (RTIs) is higher in people with congenital heart disease. RTIs are infections of the lungs and airways, such as pneumonia.

Symptoms of an RTI can include:

• a cough, which can be severe and involve coughing up phlegm and mucus
• wheezing
• rapid breathing
• chest tightness

Treatment for an RTI depends on the cause. Most are caused by viruses and do not require antibiotics. Infections caused by bacteria may be treated with antibiotics.

People with congenital heart disease also have an increased risk of developing endocarditis. This is an infection of the lining of the heart and valves, or both. If it's not treated, it can cause life-threatening heart damage.

Symptoms of endocarditis can include:

• a high temperature
• chills
• loss of appetite
• headache
• muscle and joint pain
• night sweats
• shortness of breath
• persistent cough

Endocarditis will need to be treated in hospital with antibiotic injections.

The condition usually develops when an infection in another part of the body, such as on the skin or the gums, spreads through the blood and into the heart.

As gum disease can potentially lead to endocarditis, it's very important to maintain excellent oral hygiene if you have congenital heart disease and have regular check-ups at the dentist.

It's also usually recommended that you avoid having any cosmetic procedure that involves piercing the skin, such as tattoos.

Some types of congenital heart disease can cause the blood pressure inside the arteries that connect the heart and lungs to be much higher than it should be. This is known as pulmonary hypertension.

Symptoms of pulmonary hypertension can include:

• shortness of breath
• extreme tiredness
• dizziness
• feeling faint
• chest pain
• a rapid heartbeat

A range of medicines can be used to treat pulmonary hypertension.

Read more about treating pulmonary hypertension.

Children and adults with congenital heart disease are at risk of developing different types of heart rhythm problems. These may come from the top of the heart (atrial arrhythmia) or from the ventricular chambers, which are more concerning (ventricular arrhythmia).

At rest, a normal heart rate is between 60 and 100 beats a minute. The heart may either beat too slowly, which may require a pacemaker, or too fast, which may require medicine or (rarely in a child) an implantable cardioverter defibrillator to deliver an electric shock to the heart to stop the rhythm problem.

There are 2 particularly fast rhythms that come from the top of the heart and become more common with age. These are atrial fibrillation and atrial flutter.

There's a small risk of sudden cardiac death in people with a history of congenital heart disease, but this is uncommon. Identifying people at risk of sudden cardiac death is difficult, but those with a high risk of ventricular arrhythmias are usually fitted with an implantable cardioverter defibrillator.

Heart failure is where the heart can't pump enough blood around the body to meet the body's needs. It can occur shortly after a baby with a severe congenital heart defect is born, or as a later complication of any treated or untreated type of congenital heart disease.

Symptoms of heart failure can include:

• breathlessness when you're active or sometimes resting
• extreme tiredness and weakness
• swelling in the abdomen (tummy), legs, ankles and feet

Treatments for heart failure can include medicine and the use of an implanted device such as a pacemaker.

Read more about treating heart failure.

Having a history of congenital heart disease can also increase the risk of a blood clot forming inside the heart and travelling up to the lungs or brain.

This can lead to a pulmonary embolism (where the blood supply to the lungs is blocked) or a stroke (where the blood supply to the brain is blocked).

Medications can be used to prevent, dissolve or remove blood clots.

Many women with congenital heart disease can have a healthy pregnancy, but pregnancy puts an extra strain on the heart and can cause problems.

If you have congenital heart disease and you're considering having a baby, you should discuss it with your heart specialist (cardiologist) before getting pregnant.

If you have congenital heart disease and you become pregnant, you must get help from healthcare professionals with experience in treating pregnant women with a history of the condition.

Read more about congenital heart disease in pregnancy.

If you have congenital heart disease and become pregnant, your congenital heart specialist will usually arrange an echocardiogram (heart scan) for your baby approximately 20 weeks into your pregnancy. This is to check whether your baby has any evidence of congenital heart disease. This scan will be in addition to your usual antenatal ultrasound scans.