(Date: November 2016. 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?

Mephedrone (also known as M-CAT, White Magic, Meow Meow) is a stimulant that is used recreationally and causes changes in mood and behaviour.

Is it safe to use mephedrone during pregnancy?

Use of mephedrone in pregnancy is not advised. When a pregnant woman uses mephedrone it enters her bloodstream and crosses the placenta to the baby. The effects on a developing baby from mephedrone exposure are unclear as very few pregnant women who use mephedrone have been studied. However, mephedrone is related to a class of drugs called amphetamines. Use of amphetamines in pregnancy has been linked to a number of adverse pregnancy outcomes (see below). There is a theoretical risk that exposure to mephedrone in the womb may cause similar effects and that it may result in long-lasting changes in a baby’s brain.

What if I have already used mephedrone during pregnancy?

If you are pregnant and use mephedrone you should speak to your doctor or midwife about this. They will be able to help you to get support to safely stop using mephedrone.

Can using mephedrone during pregnancy cause 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 exposure to recreational drugs could potentially cause birth defects.

No studies have assessed birth defect rates in babies born to women who used mephedrone in early pregnancy. 

Can using mephedrone in pregnancy cause miscarriage or stillbirth?

No studies have assessed miscarriage or stillbirth rates in pregnant women who use mephedrone. 

Can using mephedrone in pregnancy cause low birth weight in the baby?

No studies have assessed rates of low birth weight in babies born to women who used mephedrone in pregnancy. Amphetamines are a class of drugs related to mephedrone. Use of amphetamines in pregnancy has been linked to low infant birth weight. There is a theoretical risk that mephedrone might have the same effect and research into this subject is therefore required.

Can using mephedrone in pregnancy cause premature delivery (<37 weeks)?

No studies have assessed rates of premature delivery in women who used mephedrone in pregnancy. However, studies have shown that use of amphetamines (drugs related to mephedrone) in pregnancy may increase the risk of premature delivery.  There is a theoretical risk that mephedrone might have the same effect and research into this subject is therefore required.

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

Withdrawal symptoms at birth
There are a small number of reported cases that suggest that exposure to mephedrone in pregnancy can lead to withdrawal symptoms in the newborn baby (such as jitteriness, increased muscle tone, and high-pitched screaming).

Amphetamines are a class of drugs related to mephedrone. Use of amphetamines in pregnancy has also been linked to withdrawal symptoms in newborn babies. The risk of these problems is highest when amphetamines have been used throughout pregnancy or in the weeks before delivery. If you have used mephedrone regularly during pregnancy it is important to let your doctor or midwife know. They might advise that you give birth in a unit that can monitor and treat your baby for withdrawal symptoms if necessary.

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 exposure to certain substances at any stage of pregnancy could have a lasting effect on a child’s learning or behaviour.

No studies have addressed whether exposure to mephedrone in the womb can affect learning and behaviour in the child. Because mephedrone affects mood and behaviour there are theoretical concerns that it might have long-lasting effects on a baby’s developing brain that affect learning and concentration.

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.

If you have used mephedrone during pregnancy it is best for you and your baby that you tell your doctor or midwife as soon as possible. They will then be able to make sure that you and your baby receive extra monitoring or support if necessary.

Are there any risks to my baby if the father uses mephedrone?

No studies have specifically investigated whether mephedrone used by the father can harm the baby through effects on the sperm, however most experts agree that this is very unlikely. More research on the effects of drug and medicine use in men around the time of conception 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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