Leflunomide

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Date: April 2026, Version 5.0

Quick read

Leflunomide is rarely used in pregnancy as there is not enough evidence to say that it is safe.

What is it?

Leflunomide (Arava®) is a medicine which dampens downs an overactive immune system. It is used to treat rheumatoid arthritis and psoriatic arthritis.

Benefits

What are the benefits of taking leflunomide in pregnancy?

Using leflunomide can help keep inflammatory arthritis under control which should reduce your symptoms and help prevent damage to your joints.

However, leflunomide is not recommended in pregnancy as there is not enough information to confirm that it is safe for your baby. 

Leflunomide stays in the body for a long time after you stop taking it. If you have taken leflunomide in the last two years and are planning a pregnancy, or if you have an unplanned pregnancy, please contact your doctor as soon as possible. You may be offered a treatment to help remove any remaining leflunomide from your body.

Risks

Are there any risks of taking leflunomide during pregnancy?

It is not clear whether leflunomide increases the risk of pregnancy complications. Studies in animals suggest leflunomide might cause birth defects, but information from human pregnancies does not show this.

Research suggests that if women who get pregnant while taking leflunomide are quickly given treatment to remove the leflunomide, there is no increased risk of birth defects in their babies.

Alternatives

Are there any alternatives to taking leflunomide in pregnancy?

Yes. Other drugs that work in a similar way to leflunomide, but are better studied in pregnancy, can be used.

No treatment

What if I prefer not to take leflunomide in pregnancy?

Your doctor will be happy to discuss the risks and benefits of using other medicines to treat your inflammatory arthritis during pregnancy.

Will my baby need extra monitoring during pregnancy?

Women in the UK should be offered a very detailed scan at around 20 weeks of pregnancy as part of their routine antenatal care. If your baby was exposed to leflunomide in the first trimester, you might be offered this scan slightly earlier.

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

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

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.