(Date of issue: August 2015. Version: 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?
Bupropion (Zyban®) is a medicine that in the UK is prescribed to help people to stop smoking. In other countries bupropion is used at higher doses as an antidepressant.
Is it safe to take bupropion in pregnancy?
There is currently not enough information to assess whether bupropion use in pregnancy is safe for a baby in the womb. Use of bupropion to stop smoking is therefore not advised during pregnancy. In the UK use of nicotine replacement therapy (NRT) is preferred for women who are not able to stop smoking on their own.
Smoking in pregnancy is not only harmful to the mother, but also to the baby. It increases the chance of the pregnancy ending in miscarriage, and of the baby having a birth defect, being low birth weight, being born prematurely or stillborn. It is therefore best to quit smoking before becoming pregnant. For some women treatment with bupropion in pregnancy might be considered on an individual basis. Your doctor is the best person to help you decide what is right for you and your baby. When deciding whether to take bupropion during pregnancy it is important to weigh up how necessary bupropion is to your health against any possible risks to you or your baby, some of which might depend on how many weeks pregnant you are.
This leaflet summarises the scientific studies relating to the effects of bupropion on a baby in the womb.
What if I have already taken bupropion 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 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 bupropion 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.
None of the five studies that have investigated this have provided strong evidence that babies whose mothers took bupropion in the first trimester of pregnancy are any more likely to have a birth defect than babies of healthy women who did not take bupropion. Together, these studies have investigated malformation rates in around 2,000 pregnancies. Most of the women in these studies were taking bupropion as an antidepressant and would therefore have taken higher doses than are used to help people stop smoking.
A number of studies have investigated whether certain specific birth defects are more likely in babies exposed to bupropion in the womb.
Five studies investigated whether heart defects are more common in babies of mothers who took bupropion in pregnancy. Together, these studies have investigated rates of heart defects in around 10,000 pregnancies. The majority of the studies found no increased risk of any of the heart defects studied. Where a study found a possible link with a specific heart defect, other studies did not. There is therefore currently no proof that bupropion use in early pregnancy increases the risk of heart defects in the baby, but further research is required to confirm this.
Other studies have provided no evidence that bupropion use in early pregnancy increases the chance of the baby having a limb defect, a neural tube defect (such as spina bifida), cleft lip and/or palate, hypospadias (where the opening of the penis is on the underside rather than the tip), or gastroschisis (where some of the abdominal organs protrude through a hole next to the tummy button).
Can taking bupropion in pregnancy cause miscarriage?
Only one small study has investigated risk of miscarriage. The results of this study, in which women were taking bupropion as an antidepressant, do not prove that bupropion use in pregnancy causes miscarriage. More research into the use of bupropion in pregnancy is, however, required to confirm this finding.
Can taking bupropion in pregnancy cause stillbirth?
A single small study found no evidence of a link between stillbirth and use of bupropion in pregnancy. Women in the study were using bupropion as an antidepressant or to help them stop smoking. Stillbirth rates need to be studied in more pregnant women using bupropion to confirm this finding.
Can taking bupropion in pregnancy cause preterm birth or my baby to be small at birth (low birth weight)?
Two small studies have provided no evidence that bupropion use in pregnancy (mainly to help women stop smoking) adversely affects a baby‘s growth in the womb or increases the risk of the baby being born early. Rates of low birth weight and preterm delivery in more babies of pregnant women using bupropion need to be studied to confirm this finding.
Can taking bupropion in pregnancy cause withdrawal symptoms in the newborn baby (‘neonatal withdrawal’)?
Withdrawal symptoms are thought to occur as a result of the newborn baby’s body having to adapt to suddenly no longer getting certain types of medicines through the placenta.
Neonatal withdrawal has been reported in babies who were exposed to medicines that act in the same way as bupropion. Close monitoring of your baby for a few days after birth may be advised if you have taken bupropion regularly in the weeks before delivery.
Can taking bupropion in pregnancy cause learning and 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.
A single study found evidence that children who were exposed to bupropion in pregnancy (particularly during the second trimester) were more likely to be diagnosed with attention deficit hyperactivity disorder (ADHD) by the age of 5. In this study the mothers were using bupropion to treat depression. No further studies have assessed ADHD rates in children exposed to bupropion in the womb. More studies into the rates of behavioural and learning problems in children exposed to bupropion in the womb are required before we can say whether there is a link with this medicine or whether the findings of the above study are due to other factors.
Will my baby need extra monitoring?
Most women will be offered a scan at around 20 weeks of pregnancy to look for birth defects as part of their routine antenatal care. Taking bupropion in pregnancy is not expected to cause problems that would require extra monitoring of your baby. However, if you have smoked heavily during pregnancy your baby’s growth may be monitored more closely.
If you have taken bupropion around the time of delivery your baby may require extra monitoring after birth because of the risk of neonatal withdrawal.
Are there any risks to my baby if the father has taken bupropion?
No studies have specifically investigated whether bupropion 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 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 www.uktis.org.
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.