Chlorphenamine

Print
Date: May 2025, Version 4.0

Quick read

Chlorphenamine can be used during pregnancy if recommended by a doctor.

What is it?

Chlorphenamine (Allerief®, Hayleve®; Piriton®) is a sedating (drowsy) antihistamine used to treat hay fever, skin allergies, and other allergic symptoms.

Benefits

What are the benefits of using chlorphenamine in pregnancy?

Chlorphenamine can also help you feel better if you have unpleasant symptoms caused by allergy.

Risks

Are there any risks of using chlorphenamine during pregnancy?

No. The available information does not suggest that chlorphenamine causes any harm to you or your baby during pregnancy.

Alternatives

Are there any alternatives to using chlorphenamine?

Possibly. Other medicines can be used to treat allergies. However, if chlorphenamine is recommended during pregnancy, this is because your doctor thinks it is the best treatment for you. If you have any questions you can speak to your doctor or midwife.

No treatment

What if I prefer not to take chlorphenamine?

You might be able to improve some allergy symptoms without using a medicine. However, some women might need an antihistamine so that they can carry on their daily life.

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. Using chlorphenamine in pregnancy would not normally require extra monitoring of your baby.  

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

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

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.