Montelukast

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Date: May 2025, Version 4.0

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Montelukast can be used during pregnancy if prescribed by a doctor.

What is it?

Montelukast (Singulair®) is an asthma medicine that is given as an add-on treatment for people whose symptoms are not fully controlled with inhalers.

Benefits

What are the benefits of using montelukast in pregnancy?

Montelukast can help to keep asthma well-controlled. This is important to prevent serious complications for both you and your baby.

Risks

Are there any risks of using montelukast during pregnancy?

The available information does not raise concern that use of montelukast in pregnancy causes problems for your baby.

Alternatives

Are there any alternatives to using montelukast?

Not usually. You will only be prescribed montelukast when your asthma is not controlled by inhalers alone. It is important to keep taking your combination of asthma medicines.

No treatment

What if I prefer not to take montelukast?

Uncontrolled asthma can put you and your baby at risk. It is important not to change your asthma treatment unless your doctor tells you to.

Will my baby need extra monitoring?

Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care. Using montelukast in pregnancy does not require extra monitoring of your baby.  

Are there any risks to my baby if the father has taken montelukast?

We do not expect any increased risk to your baby if the father takes montelukast.

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.