(Date: July 2021. Version: 2)

This factsheet has been written for members of the public by the UK Teratology Information Service (UKTIS). UKTIS is a not-for-profit organisation funded by the UK Health Security Agency (UKHSA) on behalf of UK Health Departments. UKTIS has been providing scientific information to health care providers since 1983 on the effects that medicines, recreational drugs and chemicals may have on the developing baby during pregnancy.

What is it?

Ustekinumab (also known as Stelara®) is a medicine that dampens the immune response. It is used to treat some autoimmune diseases, including plaque psoriasis, psoriatic arthritis, Crohn’s disease and ulcerative colitis.

What are the benefits of using ustekinumab in pregnancy?

Ustekinumab helps to stop the immune system from attacking the body. It controls the unpleasant and often disabling symptoms of some autoimmune diseases, and helps to prevent ongoing damage to tissues and organs. It can also reduce the risk of some adverse pregnancy outcomes that have been linked to poorly controlled autoimmune disease, including miscarriage, preterm delivery and low infant birth weight.

Are there any risks of using ustekinumab during pregnancy?

The small amount of data available suggests that ustekinumab is unlikely to harm the baby but further studies are ideally required.

There are concerns that ustekinumab might affect the baby’s immune system for a while after birth; because of this, live vaccines might be harmful. It is therefore recommended that babies exposed in the womb to ustekinumab do not receive live vaccines until they are at least six months old. In practice, this means that these babies will not be able to receive the rotavirus vaccine course (as this must be complete by four months of age), and if BCG vaccination is required it will be delayed until the baby is six months old.

Are there any alternatives to using ustekinumab in pregnancy?

Yes; other immunosuppressant medicines can be used in pregnancy so switching to a different drug may be an option. Some women may also find that their illness improves by itself as pregnancy progresses, and so a specialist may advise that treatment can be reduced.

Women on ustekinumab who are planning a pregnancy or who accidentally conceive should arrange to see their doctor or specialist as soon as possible. This is to check whether ustekinumab is still the best treatment and to make sure the dose is correct.

Pregnant women are advised not to change or stop their medication without speaking to their doctor.

What if I prefer not to use ustekinumab during pregnancy?

Pregnant women who have poorly controlled autoimmune disease may be at risk of adverse pregnancy outcomes, including miscarriage, preterm delivery and low infant birth weight. To help reduce the chance of these outcomes and to stop an autoimmune disease from flaring, some women will be advised to continue taking ustekinumab in pregnancy. A doctor will only prescribe medicines when necessary and will be happy to talk through about any concerns that you may have.

Will I or my baby need any extra monitoring?

As part of routine antenatal care, most women will be offered a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. Because there is not much information on ustekinumab use in pregnancy, women taking this may be offered extra monitoring as a precaution.

Are there any risks to my baby if the father has used ustekinumab?

There is currently no evidence that ustekinumab used by the father can harm the baby through effects on the sperm.

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

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General information 

Up to 1 out of every 5 pregnancies ends in a miscarriage, and 1 in 40 babies are born with a birth defect. These are referred to as the background population risks.  They describe the chance of these events happening for any pregnancy before taking factors such as the mother’s health during pregnancy, her lifestyle, medicines she takes and the genetic make up of her and the baby’s father into account.

Medicines use in pregnancy

Most medicines used by the mother will cross the placenta and reach the baby. Sometimes this may have beneficial effects for the baby.  There are, however, some medicines that can harm a baby’s normal development.  How a medicine affects a baby may depend on the stage of pregnancy when the medicine is taken. If you are on regular medication you should discuss these effects with your doctor/health care team before becoming pregnant.

If a new medicine is suggested for you during pregnancy, please ensure the doctor or health care professional treating you is aware of your pregnancy.

When deciding whether or not to use a medicine in pregnancy you need to weigh up how the medicine might improve your and/or your unborn baby’s health against any possible problems that the drug may cause. Our bumps leaflets are written to provide you with a summary of what is known about use of a specific medicine in pregnancy so that you can decide together with your health care provider what is best for you and your baby.   

Every pregnancy is unique. The decision to start, stop, continue or change a prescribed medicine before or during pregnancy should be made in consultation with your health care provider. It is very helpful if you can record all your medication taken in pregnancy in your hand held maternity records.

Disclaimer: This information is not intended to replace the individual care and advice of your health care provider. New information is continually becoming available. Whilst every effort will be made to ensure that this information is accurate and up to date at the time of publication, we cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes following decisions made on the basis of this information. We strongly advise that printouts should NOT be kept for any length of time, or for “future reference” as they can rapidly become out of date.

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