﻿ bumps - best use of medicine in pregnancy


(Date: October 2018. Version: 3)


What is it?

Leflunomide is a medicine used to treat inflammatory arthritis (such as rheumatoid and psoriatic arthritis).

Is it safe to take leflunomide in pregnancy?

Animal studies have suggested that leflunomide can cause birth defects. Although results from animal studies cannot always be directly applied to humans, until more detailed information about women who have taken leflunomide is collected and studied, we have to assume that leflunomide may not be safe to use during pregnancy. For this reason, women taking leflunomide are generally advised not to become pregnant.

Leflunomide stays in the body for more than a year after a person has stopped taking it. It is therefore recommended that women should wait for two years after stopping treatment with leflunomide before attempting to become pregnant. If you become pregnant or are planning a pregnancy and have been on leflunomide in the last two years then you should see your doctor as soon as possible as you may need treatment to ‘washout’ the leflunomide from your body.

What if I have already taken leflunomide during pregnancy?

If you become pregnant whilst taking leflunomide, or within two years of stopping it, you should consult your doctor as soon as possible. They will be able to advise you on switching medicines to control your arthritis and may also offer leflunomide ‘washout’ treatment.

Can taking leflunomide in pregnancy cause my baby to be born with birth defects?

Women who become pregnant while taking leflunomide, or who conceive within two years of stopping treatment, do not seem to have a higher chance of having a baby with a birth defect than women not taking leflunomide, provided that leflunomide is stopped when pregnancy is recognised and washout treatment is given. Only a relatively small number of pregnancies exposed to leflunomide have been studied (around 450) and more information therefore needs to be collected.

Can taking leflunomide in pregnancy cause miscarriage?

Exposure to leflunomide in early pregnancy does not seem to increase the chance of miscarriage. However, further research is required to confirm this as data is limited.

Can taking leflunomide in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?

It is difficult to assess the effect of leflunomide on pre-term birth and low birth weight because inflammatory arthritis has an effect on pregnancy.

One small study showed that taking leflunomide in the second and third trimesters was not linked to preterm birth or low birth weight in the baby. However, a separate small study found that women taking leflunomide during pregnancy were more likely to have a premature baby or to have a baby with a lower than average birth weight. More research is therefore required before any firm conclusions can be drawn.

Can taking leflunomide in pregnancy cause stillbirth?

No studies have been carried out that have specifically investigated the chance of stillbirth in pregnancies exposed to leflunomide.

Can taking leflunomide in pregnancy cause learning or behavioural problems in the child?


No studies have investigated learning and behaviour in children exposed in the womb to leflunomide.

Will my baby need extra monitoring?

If you have become pregnant whilst taking, or within two years of taking, leflunomide, even if you have been treated with colestyramine, your obstetrician may offer you a detailed fetal ultrasound scan to check for birth defects in your baby.

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

It is unlikely that there would be an increased risk to your baby if the father took leflunomide before or at around the time you became pregnant. However, it is recommended that men who have used leflunomide within the last two years and who are planning a pregnancy with their partner should seek advice from their rheumatologist with regards to stopping the drug and/or washout prior to trying to conceive.

Who can I talk to if I have questions?


Feedback request 


General information 


Medicines use in pregnancy








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