Pregnancy and congenital heart disease

Most women with congenital heart disease (CHD) can have a successful pregnancy, but it requires careful planning and discussion with your adult CHD healthcare team. Pregnancy has its risks – even in healthy women – but there may be greater risk for women with CHD and their baby. For some women, the risk is high enough that pregnancy is not recommended.

A woman’s level of risk depends on her heart defect, how well her heart works, and whether or not she is experiencing complications, such as an irregular heartbeat (arrhythmia) or heart failure. Sometimes surgery or medication is recommended to improve a woman’s health before she becomes pregnant to reduce her risk during pregnancy.

Women with mechanical valves have to take a blood thinner, which is a risk to fetal development. Pregnancy also makes managing a blood thinner more difficult and less stable for the mother.

Women with tissue valves tend to do well during pregnancy as long as the valve is working well and there are no other complications.

If you are thinking of becoming pregnant, it is important to talk to a cardiologist who is trained to treat women with CHD during pregnancy.

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The approximate risk of a child being born with CHD

3 to 5%

The risk of a parent with CHD having a baby with CHD

50%

The risk can rise up to 50%, depending on the parent's type of CHD

Before pregnancy, I went through a battery of tests and a consult with a maternal fetal medicine cardiac team. We felt comfortable with the risks. My ACHD cardiologist, and high-risk obstetrician were very diligent and extra attentive . I didn't have any cardiac complications.

Genetic counselling

Genetic counselling before you become pregnant may be valuable for you. Your healthcare team will collect detailed medical, surgical and family histories to try to understand if your CHD is genetic. Molecular genetic testing may be suggested to you. After the information has been collected, your genetic counsellor and the rest of the team will review your results, explain their findings and talk to you about how they impact you and your family.

The impact of pregnancy on the heart

Pregnancy makes your heart work much harder. It has to pump almost twice as much blood per minute. Blood pressure changes and irregular heartbeat (arrhythmia) are common. All of these changes are normal and occur in all pregnant women. But for a heart affected by CHD, these changes can be a serious burden.

Women with mechanical valves are at high risk because they have to take a blood thinner, which poses a risk to fetal development. Also, pregnancy makes managing a blood thinner more difficult and less stable for the mother. Women with tissue valves tend to do well during pregnancy as long as the valve is working well and there are no other complications.

Jack Colman

ACHD cardiologist

The long-term effects of pregnancy and delivery on women with CHD are not yet completely known. Most women tolerate pregnancy quite well, but some may have damage to their heart. For women with severe CHD, the risks are much higher and may even result in death.

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Pregnancy and lifestyle recommendations

There are things you can do to help make your pregnancy safer:

Be as fit as possible before and during pregnancy and continue to keep active with regular exercise such as walking or swimming. Women with complex heart conditions should talk to their cardiologist before starting an exercise program.
Fatigue is common in the first three months of pregnancy, so make sure you get extra rest.
Keep from getting overheated, and avoid saunas and hot tubs.
Sexual relations during pregnancy are not a problem for most women with CHD.

Health Canada has important tips for a healthy pregnancy.

Make an appointment with your adult CHD cardiologist before becoming pregnant, and stay in communication with them during and after your pregnancy. If you have a moderate or complex condition, you should be managed throughout your pregnancy by an experienced special pregnancy team including an adult CHD cardiologist and obstetrician knowledgeable about pregnancy and heart disease. It is important to maintain a healthy lifestyle, and to follow your adult CHD team’s recommendations.

Key messages

Most women with CHD can have a successful pregnancy, but it requires careful planning and discussion.
For some women with CHD, pregnancy is not recommended.
The risk of having a baby with CHD is greater if a parent has CHD.
Pregnancy can cause serious damage to the heart, especially in women with severe CHD.
It is important to maintain a healthy lifestyle, and follow your adult CHD team’s recommendations.

Related information

More information about pregnancy in women with CHD from the Adult Congenital Heart Association (US).

To learn more about CHD, check our other webpages.

This information was written by Shelagh Ross – who lives with congenital heart disease – in collaboration with cardiologists Jack Colman and Lorna Swan, ACHD program, Peter Munk Cardiac Centre and University of Toronto.

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