Pulmonary Stenosis

What is it?

The pulmonary valve is made of flaps (medical term: cusps) that open and close. When the pulmonary valve opens it allows blood to leave the right side of the heart and be pumped to the lungs. (see The Normal Heart) When the pulmonary valve becomes stiff, it is unable to open fully (medical term: stenosis). The narrowed pulmonary valve makes it more difficult for blood to exit the right side of the heart and the heart needs to work harder to pump blood. Pulmonary valve stenosis is graded as mild, moderate, or severe depending on the degree of narrowing.

Most often, people with pulmonary stenosis are born with the condition. Less commonly it is part of a genetic syndrome such as Williams syndrome, Noonan syndrome, congenital Rubella syndrome or Alagille syndrome.

Generally people feel fine with pulmonary stenosis. If the pulmonary stenosis becomes severe, some people may be unable to do strenuous activity, they may be short of breath, have palpitations, feel faint or have chest pain.

How safe is it for me to become pregnant?

Pregnancy is associated with increased demands on the heart. (see Cardiovascular Changes) The ability of the body to pump blood through the narrowed valve depends upon the degree of narrowing (it is more difficult if the valve is more narrow) and the strength of the heart muscle (it is more difficult if the heart is weak).

Your valve may need to be fixed if you have severe pulmonary stenosis and have symptoms such as difficult breathing. If your valve needs to be fixed, it is much better and safer to have it fixed before a pregnancy.

Every pregnancy carries some risk for complications and this risk may be increased by underlying heart disease. All women have to consider the safety of a pregnancy, taking their underlying heart disease into account. Every person’s heart condition is different and therefore the safety of pregnancy differs too. Before proceeding with trying to have a baby you should discuss your specific condition and the details of your situation with a heart specialist who knows about the care of women with heart disease in pregnancy.

Issues for the mother

Which forms of birth control are safe?
For most women with pulmonary stenosis, the choice of birth control (medical term: contraceptive) is usually not limited by your heart disease. (see Birth Control) Contraceptive selection should be discussed with a doctor who has an understanding of your underlying heart condition.

What are my risks if I become pregnant?
In order to determine your risks during pregnancy, you should see your heart specialist before getting pregnant. You may need additional heart tests such as an echocardiogram or a magnetic resonance imaging scan (MRI scan) to better determine the risks of pregnancy. (see Heart Tests)

Most women with pulmonary stenosis do well during pregnancy. Women with severe pulmonary stenosis are at higher risk for heart problems during pregnancy. Rarely, women with severe pulmonary stenosis can develop heart failure or rhythm problems (medical term: arrhythmias). If you had heart failure or rhythm problem before pregnancy, your risk for complications during pregnancy is higher. Other cardiac characteristics can have an impact on pregnancy outcomes (see General Considerations). It is very important to see a heart specialist before pregnancy to discuss your risks in pregnancy.

Some medications are not safe in pregnancy. Do not stop medications without first checking with your doctor, but do check your medications out before pregnancy so you will have a plan. If you did not do that, then do so as soon as you know you are pregnant. The MOTHERISK website is an excellent resource.

Issues for the baby

The majority of babies born to mothers with pulmonary stenosis are born at term without complications.

In the general population, the risk of having a baby with congenital heart disease is about 1%. If a mother has pulmonary stenosis, the risk increases to about 5%. Genetic maternal syndromes such as Williams syndrome, Noonan syndrome or Alagille syndromes are associated with a 50% risk of being transmitted to the baby.

Women are usually offerred ultrasound screening of the baby’s heart (medical term: fetal echocardiogram) at the end of the fifth month of pregnancy (20 weeks gestation). The fetal echocardiogram can detect most major cardiac defects in the developing baby. Minor defects may not be detected until after birth.

Medical care during pregnancy and delivery

Where should I be followed?
Your specialists (heart specialist, obstetrician) will determine the frequency of follow up during your pregnancy and where you should deliver. Women with mild pulmonary stenosis may simply be followed locally. For women with severe pulmonary stenosis, care during pregnancy should occur at a center that specializes in high-risk pregnancy.

What can I do and expect during pregnancy?
Your heart specialist will arrange for check up visits during your pregnancy. In addition to your clinic visits, your doctors will arrange echocardiograms to help determine how your heart is adapting to the pregnancy.

It is important that you pay attention to symptoms during your pregnancy. Notify your doctor if you develop any worrying symptoms such as shortness of breath, swelling of your legs, heart palpitations, fainting or chest pain.

If your symptoms are worrying and you cannot get in touch with your doctor, go to your nearest emergency department. It is helpful to keep a letter from your doctor explaining your condition so that other health care professionals can better help you in an emergency situation.

Labour and delivery should be planned with your heart specialist and your obstetrician. A vaginal delivery is usually recommended.