Orlistat

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Date: September 2026, Version 1.0

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You should stop using orlistat if you find out you are pregnant. Intentional weight loss in pregnancy is not recommended.

What is it?

Orlistat (Alli®, Orlos®, Xenical®) is a drug used to help with weight loss. It works by reducing the amount of fat you absorb from your food.

Benefits

What are the benefits of using orlistat in pregnancy?

Orlistat should not be used in pregnancy. Trying to lose weight during pregnancy is not recommended.

Risks

What are the risks of using orlistat in pregnancy?

There is not much information on pregnant women who took orlistat, but the available evidence does not show that it harms the baby.

Alternatives

Are there any alternatives to using orlistat in pregnancy?

If you have a higher BMI, your midwife will be able to advise about ways to limit pregnancy weight gain through lifestyle measures, such as a healthy diet and moderate physical activity.

No treatment

What if I prefer not to take medicines in pregnancy?

Orlistat can be safely stopped in pregnancy.

Will I or my baby need extra monitoring?

As part of routine antenatal care, most women will be offered a very detailed scan at around 20 weeks of pregnancy to check the baby’s development. No extra monitoring for major birth defects is required following use of orlistat.

Are there any risks to my baby if the father has used orlistat?

There is no evidence that orlistat used by the father can harm your baby through effects on sperm.

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.