Date: October 2022, Version 4

Quick read

Leflunomide is not used in pregnancy because experiments in animals have suggested that it might affect the developing baby.

What is it?

Leflunomide (Arava®) is used to treat psoriatic and rheumatoid arthritis.


What are the benefits of using leflunomide in pregnancy?

Leflunomide reduces the symptoms of inflammatory arthritis by stopping the immune system from attacking the joints. However, leflunomide is not recommended in pregnancy as animal experiments suggest that it might cause birth defects.

Leflunomide stays in the body for a long time after treatment is stopped. Women who have taken leflunomide in the last two years and are planning a pregnancy or discover they are pregnant should contact their doctor. They might be offered a treatment to ‘wash out’ leflunomide from the body.


What are the risks of using leflunomide in pregnancy?

It is unclear if there are any risks. While animal experiments suggest leflunomide can cause birth defects, information from human pregnancies does not show this.

There is quite a lot of evidence that women who become pregnant while taking leflunomide, or soon after treatment has stopped, are not at high risk of having a baby with a birth defect if they are given treatment in early pregnancy to ‘wash out’ the leflunomide from the body.


Are there any alternatives to using leflunomide in pregnancy?

Usually. Other drugs that are safer in pregnancy can be used to treat inflammatory arthritis. Some women find that an inflammatory illness improves during pregnancy and so a doctor may advise that treatment can be altered.

Women taking leflunomide who are planning a pregnancy or who become pregnant should arrange to see their doctor or specialist as soon as possible to decide on the best treatment, and also determine whether leflunomide ‘wash out’ treatment is required.

No treatment

What if I prefer not to take medicines during pregnancy?

Poorly controlled inflammatory disease puts pregnancies at risk as it is linked to miscarriage, preterm delivery, and low infant birth weight. To help reduce the chance of these outcomes and to stop an inflammatory disease from flaring, most women will be advised to take some form of medication during pregnancy.

A doctor will only prescribe medicines when necessary and will be happy to talk about any concerns.

Will I or my baby need extra monitoring?

As part of routine antenatal care in the UK, women are invited for a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. No further scans to check for birth defects will be required, although extra growth scans may be offered.

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

The manufacturer of leflunomide suggests that men taking leflunomide should not father a pregnancy until six months after treatment has been stopped and a ‘wash out’ treatment has been given. Men taking leflunomide who are planning to father a pregnancy should speak to their doctor or specialist for advice.

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.