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Date: July 2026, Version 1.2

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Cystic fibrosis medication (CFTR modulators) can be used in pregnancy.

What are CFTR modulators? 

CFTR modulators are medicines used to treat cystic fibrosis (CF). Examples include: deutivacaftor, elexacaftor, ivacaftor, lumacaftor, tezacaftor and vanzacaftor. Some CF medicines contain combinations of CFTR modulators. Brand names of these combination medicines include: Kaftrio®, Symkevi®, Orkambi®, Alyftrek®, and Kalydeco®.

Benefits

What are the benefits of using a CFTR modulator in pregnancy?

CFTR modulators treat CF by reducing the build-up of thick, sticky mucus in your body. This helps to control the problems caused by CF, including chest infections and damage to your lungs, pancreas, and other organs. 

Using CFTR modulators improves your lungs and makes sure that you can get the nutrients that you need from food. Good treatment of your CF reduces the chances of pregnancy complications such as preterm delivery and low birth weight in your baby.

 

Risks

What are the risks of using a CFTR modulator during pregnancy?

There is not much information on use of CFTR modulators in pregnancy. However, there is no indication that these medicines will harm your baby.

Alternatives

Are there any alternatives to using a CFTR modulator in pregnancy?

Probably not. CFTR modulators are the most effective treatment for CF. Your specialist is likely to recommend that you continue CFTR treatment during pregnancy to keep both you and your baby as healthy as possible.

No treatment

What if I prefer not to use CFTR modulators in pregnancy?

It is vital that CF remains well-controlled while you are pregnant. If your doctor has prescribed a CFTR modulator, it is important to take it as recommended.

Are there any risks to my baby if the father uses a CFTR modulator?

There are no concerns that a CFTR modulator used by the father around the time of conception can harm your baby through effects on sperm.

Will I or my baby need extra monitoring during pregnancy or around the time of delivery?

As part of routine antenatal care in the UK, you will be offered a detailed scan at around 20 weeks of pregnancy to check your baby’s development.
 
You will be cared for by an obstetrician during pregnancy due to your CF. Your baby’s growth will be more closely monitored in later pregnancy as CF may lead to your baby being smaller than average.
 
Cataracts (clouding of the eye lens) are a rare side effect in children who take CFTR modulators. It is unclear whether exposure to a CFTR modulator during pregnancy can have this effect. As a precaution, your baby might be offered an appointment with an eye specialist before three months of age to check for cataracts.
 
CFTR modulators can affect liver function in some people. Your baby may require a blood test after birth to check liver function.

All newborn babies born in the UK receive a heel prick blood test to check for some health conditions including CF. Exposure to CFTR modulators in the womb can affect the results of the CF test.  Your baby may therefore require extra genetic testing for CF after birth.

Who can I talk to if I have questions?

If you have any questions regarding the information in this leaflet, please discuss them with your health care provider. They can access more detailed medical and scientific information from www.uktis.org.

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system (MyBump Portal) allows women who are currently pregnant to create a secure record of their pregnancy, collected through a series of questionnaires. You will be asked to enter information about your health, whether or not you take any medicines, your pregnancy outcome and your child's development. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit the MyBump Portal to register.

General information
Sadly, miscarriage and birth defects can occur in any pregnancy.

Miscarriage occurs in about 1 in every 5 pregnancies, and 1 in every 40 babies are born with a birth defect. This is called the ‘background risk’ and happens whether medication is taken or not.

Most medicines cross the placenta and reach the baby. For many medications this is not a problem. However, some medicines can affect a baby’s growth and development.

If you take regular medication and are planning to conceive, you should discuss whether your medicine is safe to continue with your doctor/health care team before becoming pregnant. If you have an unplanned pregnancy while taking a medicine, you should tell your doctor as soon as possible.

If a new medicine is suggested for you during pregnancy, please make sure that the person prescribing it knows that you are pregnant. If you have any concerns about a medicine, you can check with your doctor, midwife or pharmacist.

Our Bumps information leaflets provide information about the effects of medicines in pregnancy so that you can decide, together with your healthcare provider, what is best for you and your baby.