Fluconazole to treat thrush (150mg tablet)

(Date: May 2016. Version: 2.2)

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?

Fluconazole (Diflucan®) is a medicine used to treat fungal infections. The standard dose for treatment of vaginal thrush is a single 150mg tablet taken orally.

Is it safe to take fluconazole in pregnancy?

When deciding whether or not to take fluconazole during pregnancy it is important to weigh up the benefits of its use against the known or possible risks, some of which will depend on how many weeks pregnant you are.

Most pregnant women with vaginal thrush will be advised to first try a medicine called clotrimazole that is generally considered safe in pregnancy and comes in the form of a cream or a pessary that is inserted into the vagina. If this does not clear up the thrush a single tablet (usually 150mg) of fluconazole is sometimes prescribed.

Most scientific studies suggest that a single 150mg dose of fluconazole during pregnancy will not harm a baby in the womb.

Thrush is very common in pregnancy. 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.

What if I have already taken fluconazole during pregnancy?

If you have taken any medicines it is always a good idea to let your doctor know that you are pregnant so that, if appropriate, you can decide together whether you still need the medicines that you are on and to make sure that you are taking the lowest dose that works.

Can taking fluconazole in pregnancy cause birth defects in my baby?

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.

Some (but not all) studies have found that babies born to women who took standard dose fluconazole in early pregnancy might be at increased risk of having certain types of heart defect or of cleft lip and palate. Further research is required to confirm these findings. In the meantime it is advisable for pregnant women to use clotrimazole cream and/or pessaries rather than fluconazole tablets to treat vaginal thrush during pregnancy. An overview of the studies investigating fluconazole use in pregnancy and risk of birth defects in the baby is presented below.

Heart defects
One large study that reanalysed data from three smaller studies found that babies born to women who took standard dose fluconazole in early pregnancy were at slightly increased risk of having a heart defect. A further study showed that two specific types of heart defect called Tetralogy of Fallot and hypoplastic left heart might be more common in babies of women taking standard doses of fluconazole in early pregnancy. A third study did not find that babies born to women who used standard dose fluconazole were at increased risk of Tetralogy of Fallot, but did show that they might be at increased risk of having another heart defect called transposition of the great arteries. Because Tetralogy of Fallot, hypoplastic left heart, and transposition of the great arteries are rare and recognised as sometimes having a genetic cause, it is very difficult to study a possible link with a particular medicine. Even if taking fluconazole is one day confirmed to increase the risk of these heart defects, the likelihood of a baby having one of these defects would still be extremely small.

Cleft lip and palate
One study showed that babies born to women who took standard dose fluconazole in early pregnancy were at increased risk of having cleft lip and palate, but a further study did not agree with this finding.

Very high doses of fluconazole (400-800mg a day for long periods) when used in the first trimester to treat life-threatening fungal infections can cause certain birth defects. Please see the separate bumps leaflet on high dose fluconazole therapy for further information.

Can taking fluconazole in pregnancy cause miscarriage?

A large study of over 3,000 pregnant women has shown that women who took fluconazole tablets in early pregnancy were more likely to have a miscarriage than women who used antifungal medicines applied to the skin of the affected area. Because these results are from just one study, more research is required to confirm this finding. In the meantime it is advisable for pregnant women to stick to guidelines which advise using clotrimazole cream and/or pessaries rather than fluconazole tablets to treat vaginal thrush.

Can taking fluconazole in pregnancy cause stillbirth?

A large study of over 3,000 pregnant women has shown that women who took fluconazole tablets in early pregnancy were no more likely to have a stillbirth than women who did not use antifungal medicines in pregnancy, or women who used antifungal medicines applied to the skin of the affected area. Because these results are from just one study, more research is required to confirm this finding.

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

There is no scientific evidence to suggest that women who take standard doses of fluconazole during pregnancy are more likely to have a premature baby (born before 37 weeks of pregnancy) or a low birth weight baby (weighing less than 2500g at birth). These pregnancy outcomes have, however, only been studied in limited numbers of women and further research is required.

Can taking fluconazole 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 no known link between taking fluconazole in pregnancy and learning or behavioural problems (such as ADHD or autism spectrum disorder) in the child later on in life. There are, however, no scientific studies that have specifically investigated a link with these problems.

Will my baby need extra monitoring during pregnancy?

Taking standard dose fluconazole 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 fluconazole?

We would not expect any increased risk to your baby if the father took fluconazole 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 www.uktis.org.

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

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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