Clozapine

Date: September 2024, Version 4

Quick take

Clozapine can be used in pregnancy if recommended by a specialist.

What is it?

Clozapine (Clozaril®, Denzapine®, Zaponex®) is used to treat schizophrenia and psychosis.

Benefits

What are the benefits of taking clozapine in pregnancy?

Clozapine can prevent relapse of serious mental health conditions. Its use can help a woman remain well during pregnancy and while looking after her baby.

Risks

Are there any risks of taking clozapine during pregnancy?

Clozapine use in pregnancy has not been well-studied. It, and similar drugs, are not known to harm a baby in the womb. Further information about pregnant women using clozapine is ideally required.

Clozapine can increase blood sugar levels and cause weight gain. In theory, use in pregnancy could increase the chance of gestational diabetes and lead to the baby growing faster than expected. Your baby’s growth might therefore be more closely monitored, and later in pregnancy you may be offered a test to check for gestational diabetes (‘glucose tolerance test’).

Clozapine used around the time of delivery can cause the newborn baby to have withdrawal symptoms such as jitteriness and problems with feeding and sleeping. A hospital delivery will be recommended so that your baby can be assessed after birth and supported as necessary until these symptoms pass.

Alternatives

Are there any alternatives to taking clozapine in pregnancy?

Possibly. A mental health specialist will be able to advise whether clozapine is still the best treatment during pregnancy depending on your specific circumstances.

No treatment

What if I prefer not to take medicines during pregnancy?

Clozapine use may be recommended in pregnancy to prevent relapse of a potentially serious mental health condition. If you are advised to continue clozapine in pregnancy, you can discuss the risks and benefits with your specialist.

Will my baby need extra monitoring?

Women in the UK will be offered a very detailed scan at around 20 weeks of pregnancy as part of routine antenatal care. Taking clozapine in pregnancy would not normally require extra monitoring for birth defects. Your baby’s growth will be more closely monitored in later pregnancy as clozapine use might be linked to increased birth weight.

If you have taken clozapine around the time of delivery your baby may require extra monitoring after birth because of the possible risk of neonatal withdrawal.

Are there any risks to my baby if the father has taken clozapine?

We do not expect any increased risk to your baby if the father takes clozapine.

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.

How can I help to improve drug safety information for pregnant women in the future?

Our online reporting system (MyBump Portal) allows women who are currently pregnant to create a secure record of their pregnancy, collected through a series of questionnaires. You will be asked to enter information about your health, whether or not you take any medicines, your pregnancy outcome and your child's development. You can update your details at any time during pregnancy or afterwards. This information will help us better understand how medicines affect the health of pregnant women and their babies. Please visit the MyBump Portal to register.

General information
Sadly, miscarriage and birth defects can occur in any pregnancy.

Miscarriage occurs in about 1 in every 5 pregnancies, and 1 in every 40 babies are born with a birth defect. This is called the ‘background risk’ and happens whether medication is taken or not.

Most medicines cross the placenta and reach the baby. For many medications this is not a problem. However, some medicines can affect a baby’s growth and development.

If you take regular medication and are planning to conceive, you should discuss whether your medicine is safe to continue with your doctor/health care team before becoming pregnant. If you have an unplanned pregnancy while taking a medicine, you should tell your doctor as soon as possible.

If a new medicine is suggested for you during pregnancy, please make sure that the person prescribing it knows that you are pregnant. If you have any concerns about a medicine, you can check with your doctor, midwife or pharmacist.

Our Bumps information leaflets provide information about the effects of medicines in pregnancy so that you can decide, together with your healthcare provider, what is best for you and your baby.