Paracetamol
(Date: March 2017. Version: 1.8a)
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?
Paracetamol (also known as acetaminophen in some countries) is used to treat pain and fever and can be bought without a prescription.
Is it safe to take paracetamol in pregnancy?
Paracetamol has been used by pregnant women for many years without any obvious harmful effects on the developing baby. For this reason paracetamol is usually recommended as the first choice of painkiller for pregnant women. Other painkillers, including those sold over the counter without a prescription have not been shown to be any safer than paracetamol; some are not suitable for use during certain stages of pregnancy. Although it is not possible to say that any medicine is absolutely safe to use in pregnancy, there is currently no good evidence that paracetamol will harm your baby. It is however generally recommended that women who are pregnant use the lowest dose of paracetamol that works, only for as long as needed.
Paracetamol is sold both on its own and in combination with other medications e.g. in cold and flu remedies. It is important to make sure that the other medicines in combination products can be taken in pregnancy and that you do not take more than the daily recommended dose of paracetamol.
This leaflet summarises the scientific studies relating to the effects of paracetamol on a baby in the womb. This information will help you to weigh up the benefits of using paracetamol against the known or possible risks, some of which may depend on how many weeks pregnant you are.
Can taking paracetamol in pregnancy cause a miscarriage?
No increased risk of miscarriage was identified in either of two studies of women who took paracetamol during pregnancy.
Can taking paracetamol in 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.
The majority of studies have shown that women who took paracetamol during the first three months of pregnancy are no more likely to have a baby with a birth defect than women who did not. Some studies have suggested that paracetamol use in pregnancy may increase the likelihood of male babies being born with undescended testes, although other studies have not agreed with this finding. A study using mice that was reported in the news suggested that use of paracetamol in pregnancy might reduce the levels of testosterone (a hormone important for male development) in the unborn offspring. Because this was an animal study, we do not know how it relates to human pregnancy. There is therefore currently no scientific proof that paracetamol causes birth defects, undescended testes, or changes in hormone levels.
Can taking paracetamol in pregnancy cause preterm birth?
No increased risk of giving birth too early (before 37 weeks of pregnancy) was shown in the one study which investigated this risk in women who took paracetamol during the third trimester.
Can taking paracetamol in pregnancy cause my baby to be small at birth (low birth weight)?
No increased risk of having a baby weighing less than 2500g at birth was identified with paracetamol use in pregnancy in the one study which investigated this.
Can taking paracetamol in pregnancy cause stillbirth?
No increased risk of stillbirth was identified with paracetamol use in pregnancy in the one study which investigated this.
Can taking paracetamol in pregnancy cause learning or 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 is currently a lot of research into the possible causes of learning and behavioural problems, such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD). However, this is a very difficult area to study and there is currently only limited scientific information on the subject.
A small number of studies have looked at development, behaviour, and learning in children whose mothers took paracetamol during pregnancy. These studies are summarised below:
Studies of ADHD-like behaviour:
• One small study of 4 year olds showed no link between exposure to paracetamol in the womb and problems with attention.
• One large study of 3 year olds showed a possible link between being exposed in the womb to paracetamol for more than 28 days and higher activity levels.
• One large study of children who were assessed at 5 and then again at 7 years of age, suggested that those exposed to paracetamol in the womb had a slightly increased chance of showing ADHD-like behaviour.
• Another study used two different tests to decide whether a group of children exposed to paracetamol in the womb were more likely to show ADHD-like behaviour than children not exposed. While one test showed that 7 year olds exposed to paracetamol in the womb may be at slightly increased risk of developing ADHD, the other test showed no increase in risk at this age. When the children were tested again aged 11 years, both of these tests agreed that there was no link between paracetamol use in pregnancy and increased risk of ADHD. However, when children at this age were asked about their own behaviour, those exposed to paracetamol were slightly more likely than those not exposed to say that they had certain behavioural problems that might be linked to ADHD.
• An additional study found that five year old children who had been exposed in the womb to paracetamol were no more likely to show ADHD symptoms than unexposed children.
• Although a large study of seven year olds showed that those who had been exposed to paracetamol in the womb were slightly more likely to be hyperactive and to have behavioural problems, further analysis of the data suggested that this may actually have been due to factors within the home after birth. The scientific quality of this study has been heavily criticised at scientific meetings and in letters that have been published in scientific journals.
Studies of other aspects of learning and behaviour:
• One study showed that 12 year olds who had been exposed to paracetamol in the womb were no more likely to have psychiatric problems than those who had not been exposed.
• The large study of 3 year olds described above suggested that children who had been exposed to paracetamol in the womb for more than 28 days were more likely to have problems with behaviour, communication, and motor skills (i.e. use of muscles) than children who were not exposed. Lower levels of paracetamol use in pregnancy (use for less than 28 days) also appeared to be linked to problems with motor skills.
• The small study of 4 year olds described above showed no differences in intelligence (IQ) between those exposed in the womb to paracetamol and those not exposed.
• One large study of children aged at least ten years showed that those who were exposed in the womb to paracetamol were more likely than unexposed children to be diagnosed with autism spectrum disorder (ASD) alongside ADHD-like symptoms. No link with ASD without ADHD symptoms was seen.
• One large study found that 5 year old children of women who took paracetamol during pregnancy were more likely to have reduced attention, and that some (but not all) aspects of behaviour that can indicate that a child might have autism spectrum disorder were more common in the boys, especially those who were exposed to paracetamol throughout pregnancy as opposed to occasionally. Exposure to paracetamol in the womb did not appear to have an effect on these children’s learning and motor skills.
The studies described above do not provide convincing scientific evidence that taking paracetamol in pregnancy causes problems with learning and behaviour the child. A number of doctors and scientists who are recognised experts in this subject have raised concerns about the quality of some of these studies, including the ways in which the information was collected and analysed, and the fact that other factors (such as the illness in the mother that paracetamol was being used to treat) could have caused the effects seen in children exposed in the womb to paracetamol. It has been widely reported in the media that these studies have shown that paracetamol use in pregnancy causes behavioural problems in the child. However, many experts agree that the evidence is not good enough to draw such conclusions, and that much more research is required before we can say whether the differences in learning and behaviour found in some of these studies are linked to paracetamol use in pregnancy.
Can taking paracetamol in pregnancy cause other health problems in the child?
Some scientific studies suggest that babies who were exposed to paracetamol in the womb may be more likely to experience episodes of wheezing or develop asthma in childhood. However, other studies do not confirm these findings and there is currently no firm scientific evidence that taking paracetamol in pregnancy increases your baby’s chance of wheezing or asthma later on in life. It is possible that women who need to take paracetamol are more likely to have a condition (such as asthma) that runs in families. This could explain why some studies have found a link.
Will my baby need extra monitoring during pregnancy?
As part of their routine antenatal care, most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects and to check the baby’s growth.
Taking paracetamol during pregnancy is not expected to cause any problems that would require extra monitoring of your baby
Are there any risks to my baby if the father has taken paracetamol?
We would not expect any increased risk to your baby if the father took paracetamol before or around the time your baby was conceived.
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.
Feedback request
WE NEED YOUR HELP! Do you have 3 minutes to complete a short, quick and simple 12 question user feedback form about our bumps information leaflets? To have your say on how we can improve our website and the information we provide please visit here.
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.
www.medicinesinpregnancy.org