H2 receptor antagonists

Date: March 2024, Version 4.0

Quick read

An H2RA can be used in pregnancy if other types of medicine to control stomach acid are not suitable.

What are H2 receptor antagonists (H2RAs)?

H2 receptor antagonists (H2RAs) reduce stomach acid and are used to treat indigestion, acid reflux, and stomach ulcers. H2RAs available in the UK include cimetidine (Tagamet®), famotidine, and nizatidine.


What are the benefits of taking an H2RA in pregnancy?

An H2RA can improve health and quality of life by controlling heartburn and acid reflux, and preventing symptoms and complications caused by stomach ulcers.


Are there any risks of taking an H2RA during pregnancy?

There are no clear risks of taking an H2RA in pregnancy.


Are there any alternatives to taking an H2RA in pregnancy?

Yes. If a medicine to control stomach acid is required in pregnancy, a doctor will usually first recommend a drug called omeprazole. However, if omeprazole does not work or is not suitable, an H2RA can be used.

No treatment

What if I prefer not to take medicines in pregnancy?

Other measures can be tried to treat indigestion and heartburn in pregnancy. These include eating less at any one time, avoiding fatty foods, and sleeping on extra pillows to avoid lying flat. 

Some women may be advised to take a drug to control stomach acid in pregnancy to prevent severe symptoms or to reduce the risk of complications from a stomach ulcer.

Will my baby need extra monitoring?

All women in the UK should be offered a very detailed scan at around 20 weeks of pregnancy as part of routine antenatal care. Taking an H2RA in pregnancy does not require any extra scans or monitoring of your baby.  

Are there any risks to my baby if the father has taken an H2RA?

We would not expect any increased risk to your baby if the father takes an H2RA.

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.