(Date: April 2017. 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 Public Health England 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?

Fentanyl is a very strong painkiller that can be given by mouth in tablet form, by nasal spray, via patches that are applied to the skin, or injected directly into a vein or the spine. Fentanyl is sometimes used recreationally as a drug of abuse.

Is it safe to use fentanyl in pregnancy?

Very little is known about how fentanyl might affect a baby’s development in the womb and it is therefore not possible to say that it is safe. It is, however, important that pregnant women with severe pain receive appropriate treatment. Any assessment of safety needs to weigh up the risks and benefits to both mother and baby of using fentanyl against those of not using fentanyl. The outcome of this assessment will vary from person to person and will depend on the severity of the mother’s condition.

When deciding whether to use fentanyl during pregnancy it is therefore important to weigh up how necessary it is to your health against any possible risks to you or your baby, some of which might depend on how many weeks pregnant you are.

Recreational use of fentanyl in pregnancy is not advised as there is no benefit to the health of the mother or baby in this context. Recreational fentanyl use also carries a high risk of overdose and death. If you are pregnant and use fentanyl recreationally it is important that your doctor or midwife is aware of this. If necessary, they will be able to get you help and support to safely stop using fentanyl.
This leaflet summarises the available information relating to the effects of fentanyl on a baby in the womb.

What if I have already used fentanyl during pregnancy?

If you are taking any medicines it is always a good idea to let your doctor know that you are pregnant so that you can decide together whether you still need the medicines that you are on or whether you might need to switch to a different medicine.

Can using fentanyl 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.

There are currently no large scientific studies that have investigated whether fentanyl use during the first trimester of pregnancy can cause birth defects in the baby. We have been able to identify case studies of only four babies who were born to pregnant women who used fentanyl in the first trimester. None of these babies had birth defects, however information on many more pregnancies needs to be collected before it is possible to accurately assess whether fentanyl causes birth defects.

Can taking fentanyl in pregnancy cause miscarriage, stillbirth, preterm birth, or my baby to be small at birth (low birth weight)?

No studies have specifically analysed whether these outcomes are more or less common in pregnant women taking fentanyl.

Can using fentanyl in pregnancy cause other health problems in the baby/child?

Withdrawal symptoms at birth
Withdrawal symptoms are thought to occur as the newborn baby’s body has to adapt to no longer getting certain types of medicines through the placenta. Medicines related to fentanyl are known to increase the risk of withdrawal symptoms in the baby when used around the time of delivery.

There are a small number of reports in the scientific literature of babies who had withdrawal symptoms after being exposed to fentanyl in the womb. If you have used fentanyl regularly in pregnancy it is important to let your doctor or midwife know as it might be advisable that your baby is born in a unit with facilities to monitor and treat withdrawal symptoms if necessary.

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.

There are no studies that have been specifically designed to investigate whether fentanyl exposure in the womb might affect a child’s learning and behaviour. Nearly all medicines still need to be studied to determine whether exposure in the womb might affect a child’s learning or 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.

Because the effects of taking fentanyl in early pregnancy are largely unknown, your doctor may suggest extra monitoring of your baby, including more detailed or earlier scans to detect birth defects, and more frequent reviews of your baby’s growth in the womb.

Women with some of the underlying conditions that fentanyl can be used to treat might be more closely monitored to ensure that their baby is growing and moving as expected. Women who use fentanyl recreationally might also receive extra monitoring.

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

There are no scientific reports of babies born to men who were treated with fentanyl around the time of conception. 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 fentanyl 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 www.uktis.org.

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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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