Congenital heart disease
Around 0.8% of babies are born with a cardiac abnormality – that is, something wrong with their heart, also called congenital heart disease or congenital heart defect. Thirty years ago, 80% of these babies would have died in childhood. Today, around 85% survive to adulthood, which is why heart problems in pregnant women are more common.

Even if you've had a successful operation to correct an abnormality, it doesn’t mean that you're completely cured. You'll probably have some scarring of the heart, which will 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.

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 one is different, but the risk of serious complications falls into three ranges:

low risk: For a woman with congenital heart disease, a risk from one in 1,000 to one in 100 is considered low risk (this is the most common level of risk for women with congenital heart disease)

medium risk: this is a risk of one in 100 to one in 10

high risk: this is a risk of anything from one in 10 to one in two

The only way to estimate your risk and to judge what complications, if any, you'll have during pregnancy is to have a personal assessment by a specialist. It's important to know what problems could arise. Depending on what type of congenital heart disease you have (there are more than 100 syndromes), you may suffer from fluid on the lungs, heart failure or arrhythmia (an irregular 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 who don’t get enough nourishment may be born prematurely. You'll be offered regular scans from 26 weeks to ensure that your baby is growing at the correct rate.

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 who has it, 10% of children inherit aortic stenosis from their mother, and 3% inherit tetralogy of Fallot.

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. About 80% of defects can be detected by specialist scan at 18-22 weeks of 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 doctor before starting any new exercise regime. 

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

Induction is not recommended because the prostaglandin drugs that bring on labour may overstimulate your uterus. There are drugs to calm down this overstimulation, but these 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 the mother is seriously unwell or the baby isn't growing properly.

There's no need for mothers with congenital heart disease to be automatically given a caesarean section. But it's 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.