Mifepristone

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Date: June 2026, Version 1.0

Quick read

Mifepristone is the first of two drugs used to end a pregnancy.

In most cases, taking mifepristone on its own will still lead to the pregnancy ending. If the pregnancy continues, there is no good evidence that mifepristone alone causes birth defects.

The second medicine used (misoprostol) has been linked to rare cases of birth defects if a pregnancy continues.

What is it?

Mifepristone (Mifegyne®) is used to end a pregnancy (termination/abortion). It is usually followed by a second medicine called misoprostol.

How does mifepristone work?

Mifepristone works by blocking the hormone progesterone, which is needed to maintain a pregnancy. It also helps to soften and open the cervix (entrance to the womb).

It is the first medicine taken in a two-step process to end a pregnancy. A second medicine, misoprostol, is taken afterwards. About 95 in every 100 pregnancies will end when both medicines are used together.

There is less information about women who have taken mifepristone on its own, but studies suggest that up to 88 in every 100 pregnancies will end within two weeks when only mifepristone is taken.

Make sure that you carefully follow the instructions given by your abortion provider when using these medicines and use both drugs as advised.

There is a separate Bump leaflet available on misoprostol.

What if my pregnancy continues after taking mifepristone?

In a small number of cases, using mifepristone and misoprostol may not end the pregnancy. If you think you may still be pregnant after taking these medicines, contact your doctor or abortion provider as soon as possible. You may need further checks and follow-up care.

If your pregnancy continues after taking mifepristone on its own, there is no good evidence that this causes birth defects. However, if you have also taken misoprostol, there is a small risk of birth defects. Please see the Bump leaflet on misoprostol for further information.

Who can I talk to if I have questions?

If you have any questions about 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.