Use of certolizumab in pregnancy

(Date: July 2019. Version: 1)

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?

Certolizumab pegol (Cimzia®) is often referred to as a ‘biologic’-type drug which dampens down your immune system. It is commonly used to treat arthritis (rheumatoid and psoriasis types). It is sometimes used to treat psoriasis (a skin condition).

Is it safe to use certolizumab in pregnancy?

Any woman who is using certolizumab pegol and is planning a pregnancy should ideally speak to her doctor before she becomes pregnant.
There is little information on women who have used certolizumab pegol in pregnancy. However, certolizumab pegol does not appear to cross the placenta and so the baby will not be exposed to the drug in the womb for most of the pregnancy (see below). For this reason, if you have arthritis and need a biologic, you may be switched to certolizumab pegol for pregnancy. Arthritis and psoriasis can get worse in pregnancy and the inflammatory effect of arthritis may affect the baby (for example, preventing the baby from growing). It is important that arthritis is controlled in pregnancy.
Your doctor will be able to help you to weigh up how necessary certolizumab pegol is to your health against any possible risks to you, or to your baby. Some of these risks will depend on how many weeks pregnant you are at the time of taking certolizumab pegol.
This leaflet summarises the scientific studies relating to the effects of certolizumab on a baby in the womb.

What if I have already used certolizumab pegol during pregnancy?

If you are using certolizumab pegol and become pregnant you should let your doctor know so that you can decide together whether you still need the medicines that you are on. Sometimes it is necessary to change a medicine or dosage for pregnancy.

Can using certolizumab pegol in early pregnancy cause my baby to be born with birth defects?

A baby’s body and most internal organs are formed during the first 12 weeks of pregnancy. It is mainly during this time that some medicines are known to cause birth defects.

Certolizumab pegol has been designed so that it does not cross the placenta. However, because the placenta does not function until 10 to 12 weeks of pregnancy, in theory, certolizumab pegol could reach a baby in the womb during early pregnancy.

Published case series detail the outcomes of 367 pregnancies with early exposure to certolizumab pegol. These reports do not raise alarm that certolizumab pegol causes birth defects. However, larger scientific studies and on-going data collection are needed to be certain.

Can using certolizumab pegol in pregnancy cause miscarriage?

There are currently no studies that have investigated whether miscarriage is more common in pregnant women using certolizumab pegol. Information from a small group of pregnant women gathered by the drug’s manufacturer does not raise any concerns. However, this information was not collected in a way that enables a comparison with the general population. Further scientific research is required to determine whether use of certolizumab pegol in early pregnancy increases the chance of miscarriage.

Can using certolizumab pegol in pregnancy cause stillbirth, preterm birth, or my baby to be small at birth (low birth weight)?

No studies have specifically analysed whether stillbirth, preterm birth, or low birth weight babies are more common in pregnant women using certolizumab pegol. Research into these pregnancy outcomes in women using certolizumab pegol is therefore required.

Can using certolizumab pegol in pregnancy cause learning and behavioural problems in the child?

A baby’s brain continues to develop right up until the end of pregnancy. It is therefore possible that taking certain medicines at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.

No studies have been carried out to specifically investigate whether exposure to certolizumab pegol while in the womb can affect a child’s learning and behaviour.

Will I or my baby need extra monitoring during pregnancy?

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. No additional scans to detect birth defects are required following use of certolizumab pegol, however your obstetrician may recommend additional scans to check the baby’s growth if you have arthritis.

Can using certolizumab pegol in pregnancy cause problems with the baby’s immune system after birth?

Certolizumab pegol works by blocking the activity of blood cells within the immune system that can cause autoimmune disease. However, these cells are required to fight some infections. There is a theoretical risk that use in pregnancy might increase the risk of certain infections in the newborn baby. However, because certolizumab pegol does not cross the placenta and enter the baby’s bloodstream, any effect on the baby’s immune system is minimal. Twenty three babies exposed to certolizumab pegol in the womb have been followed up, with no concerns noted about serious infections. While this is reassuring, large, well-designed studies are required to confirm this finding.

In people with a suppressed immune system, live vaccines can theoretically cause the illness that they are designed to protect against. As a precaution, the manufacturer of certolizumab pegol recommends that babies should not receive live vaccines for the five months following the mother’s last dose during pregnancy. However, a small study of 12 babies who were exposed in the womb to certolizumab and then given the rotavirus vaccine (the only live vaccine routinely given in the UK before the age of 1 year) did not show any ill effects.

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

Most experts agree that the majority of medicines used by the father are unlikely to harm the baby through effects on the sperm. However, more research on the effects of certolizumab pegol specifically, and medicine use in men around the time of conception generally, is needed.

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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