Varenicline

What is it?

Varenicline is a medicine which is used to reduce nicotine cravings in order to stop smoking.

There is strong evidence that smoking during pregnancy increases the risk of miscarriage, some birth defects, premature birth, low birth weight, and certain pregnancy complications. Pregnant women and women trying to conceive should therefore avoid smoking. Studies have shown that stopping smoking before week 20 of pregnancy can reduce the risk of having a low birth weight baby. 

If you need help to stop smoking during pregnancy please speak to your doctor or midwife. Please read the bumps information leaflet on smoking if you would like to find out more about the risks of smoking during pregnancy.

Is it safe to use varenicline in pregnancy?

There is very little information on the safety of varenicline in pregnancy. Its use in pregnancy is therefore not generally recommended. Advice can be obtained from a pharmacist or your health professional about the other options, such as nicotine replacement therapy, that are available to help you to stop smoking in pregnancy. For more information see the Bump leaflet on use of nicotine replacement therapy in pregnancy.

What if I have already taken varenicline during pregnancy?

It is always a good idea to let your doctor know that you are pregnant if you have taken any medicines in case you need any additional monitoring or treatment.

This leaflet summarises the scientific studies relating to the effects of varenicline on a baby in the womb. 

Can use of varenicline 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.

Two small studies of a total of 343 women who took varenicline in very early pregnancy provide no proof of a link with birth defects in the baby. However, most women in these studies stopped taking varenicline in the first few weeks of pregnancy, before the baby’s arms, legs and internal organs have formed. Use of varenicline in these women was therefore too early to assess whether it might cause birth defects if used after week 4 of pregnancy and later on during the first trimester.

Can use of varenicline in pregnancy cause miscarriage?

One study mentioned above does not currently raise any concerns relating to a link between varenicline use in early pregnancy and miscarriage. However, because only a very small number of women taking varenicline in early pregnancy have been studied further research is required before we can say more confidently that use of varenicline in early pregnancy does not increase the chance of miscarriage.

Can use of varenicline in pregnancy cause stillbirth?

Although there is currently no indication that use of varenicline in pregnancy causes stillbirth, a possible link has been analysed in only a very small number of women. Further research is therefore required to confirm that use of varenicline in pregnancy does not increase the chance of stillbirth.

Can use of varenicline in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?

No studies have assessed the chance of preterm birth or low infant birth weight following use of varenicline in pregnancy. Research into this subject is therefore required.

Can taking varenicline 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 development in children exposed to varenicline in the womb. Research into this subject is therefore required.

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.

Because the effects of varenicline exposure on a developing baby are largely unknown your doctor may suggest additional monitoring if you have used varenicline in pregnancy to ensure that the baby is growing as expected.

Are there any risks to my baby if the father has used varenicline?

We would not expect any increased risk to your baby if the father used varenicline 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.