Congenital heart disease in pregnancy

Around 8 in 1,000 babies (0.8%) are born with a cardiac abnormality – that is, something wrong with their heart (also called congenital heart disease or congenital heart defect). Around 85% of babies born with a heart abnormality survive to adulthood and may go on to have children themselves.

If you were born with a cardiac abnormality and have had a successful operation to correct it, this doesn't mean that you're completely cured. You'll probably have some scarring of the heart, and this may make you more prone to infections or an irregular heartbeat. Pregnancy puts your heart under significant strain, and this can lead to problems.

See a cardiologist (heart specialist)

Some women who were treated for congenital heart disease as babies or children don't realise that regular checks are important, and may not have seen a cardiologist for a check-up for many years.

Pregnancy puts extra stress on your heart, so if you have congenital heart disease ask to be referred to a cardiologist who has experience of treating pregnant women with this condition. Do this before you get pregnant, or as soon as you know that you're pregnant.

You'll be referred to a hospital maternity unit for team-based care, and you may be able to attend a special cardiac pregnancy clinic if there's one in your area. Ask your GP for details, or contact the Somerville Foundation – a charity for grown-up congenital heart disease patients.

A congenital heart disease cardiologist will assess you and plan your care. It's hard to predict the effect of congenital heart disease on a pregnancy because each case is different, but the risk of serious complications for a woman with congenital heart disease falls into three ranges:

• low risk – a risk of less than one in 100 (this is the most common level of risk)
• medium risk – a risk of one in 100 to one in 10
• high risk – a risk of more than one in 10

The only way to estimate your risk and to determine what complications, if any, you might have during pregnancy is to have a careful assessment by a specialist. It's important to know what problems could arise. Depending on what type of congenital heart disease you have, you may suffer from fluid on the lungs, heart failure or arrhythmia (an irregular and/or fast heartbeat).

Your baby

Your congenital heart disease can also affect your baby. Babies may be smaller if the mother's heart does not pump as efficiently as it should, and delivers less oxygen and nutrients to the placenta and developing baby. Babies may be born prematurely. You'll be offered regular scans from 26-28 weeks of pregnancy, to ensure that your baby is growing normally and that he or she remains healthy.

Depending on the type of congenital heart disease you have, there's a chance that your baby could inherit the condition. For example, Marfan syndrome affects half of all children born to a mother with the condition. The British Heart Foundation has information for parents on coping with a child's congenital heart disease.

You need to know as much as you can about your condition, so that your baby can get any special care if necessary when he or she is born. Many, but not all, defects in the unborn baby can be detected during pregnancy. The future management of the pregnancy and baby will be discussed with you, and a specialist cardiac paediatrician will advise you on the options available once the baby is born.

Treatment and self-management

The treatment you receive will depend entirely on what condition you have, and your cardiologist will provide you with a tailored antenatal care plan. This may mean that you have to change the drugs you take. For example, ACE inhibitors aren't recommended during pregnancy.

During your pregnancy, follow any advice your specialist gives you about managing your condition. Low-impact exercise, such as swimming and walking, is usually a good idea to keep you fit, but always speak to your midwife or doctor before starting any new exercise regime.

Labour and birth

Because of the risk of complications, the National Institute for Health and Care Excellence (NICE) recommends that women with cardiac disease should give birth in hospital, supported by a maternity team.

Depending on the type and severity of heart disease, induction may not be recommended because the prostaglandin drugs that bring on labour may overstimulate your uterus, and the drugs used to reverse this can't be given to mothers with congenital heart disease. It's best to wait for spontaneous labour (labour that starts naturally), unless the baby has to be delivered early because you are unwell or the baby isn't growing normally.

There's no need for mothers with congenital heart disease to be automatically delivered by caesarean section. However, it may be recommended that you have a pain-free labour, which means that you should have an epidural, and your doctor may use forceps or a ventouse to assist you during the delivery, as this avoids the strain of having to push the baby out.