(Date: February 2018. Version: 3)

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?

Clotrimazole (Canestan®) is a medicine that is used to treat fungal infections such as vaginal thrush. Clotrimazole is available as a cream to be applied externally, and as a pessary that is inserted into the vagina. The cream and pessary are often prescribed together.

Is it safe to use clotrimazole in pregnancy?

Clotrimazole is generally considered safe for pregnant women to use. If you are using the pessary to treat vaginal thrush during pregnancy it is recommended that you insert it with your fingers rather than with the applicator provided.

It is very common for pregnant women to suffer from thrush. If you think you have thrush it is best to consult your doctor or midwife who will advise you as to whether treatment is recommended.

Can using clotrimazole 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.

There is no scientific proof that using clotrimazole during early pregnancy increases the risk of having a baby with a birth defect. Four studies that include a total of over 5,700 pregnant women have all shown that women who used clotrimazole during early pregnancy were no more likely to have a baby with a birth defect than women who didn’t use clotrimazole.

Can using clotrimazole in pregnancy cause miscarriage?

There is no scientific proof that clotrimazole use during early pregnancy causes miscarriage.

Two studies of miscarriage have been carried out, and while one showed no increased risk with clotrimazole use, the other showed a slightly increased risk. However, women using clotrimazole in pregnancy may be more likely to be obese or to have diabetes, because these factors make women more prone to thrush. Being obese or diabetic is also known to increase a woman’s chance of having a miscarriage. It is therefore possible that these factors, and not the clotrimazole treatment, explain the slightly increased risk of miscarriage seen in the one study. More research is needed before firm conclusions can be drawn.

Can using clotrimazole in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?

There is no scientific evidence to suggest clotrimazole use during pregnancy causes women to give birth earlier or have a baby with a low birth weight (less than 2,500g).

A number of studies have looked at this, and in fact, some of these have shown that women who were treated with clotrimazole during pregnancy were less likely to have a premature baby (born before 37 weeks of pregnancy), and as a consequence were also less likely to have a low birth weight baby.

Can using clotrimazole in pregnancy cause stillbirth?

No link between clotrimazole use in pregnancy and stillbirth is known about, however no scientific studies have been carried out that have specifically investigated this.

Can using clotrimazole 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.

No studies have investigated learning and behaviour in children whose mothers used clotrimazole in pregnancy.

Will my baby need extra monitoring during pregnancy?

Using clotrimazole 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 used clotrimazole?

We would not expect any increased risk to your baby if its father used clotrimazole before or around the time you became pregnant.

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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