Alendronic acid

Date: December 2022, Version 4.1

Quick read

Bisphosphonates are not usually recommended in pregnancy as there is not enough evidence to say that they are safe for the baby.

What are they?

Bisphosphonates (alendronic acid, ibandronic acid, pamidronate disodium, risedronate sodium, sodium clodronate and zoledronic acid) are used to prevent weakening of the bones. They are used to treat bone conditions like osteoporosis and bone pain caused by cancer.


What are the benefits of using a bisphosphonate in pregnancy?

Bisphosphonates treat bone loss and bone pain. This can mean that you are more mobile and in less pain. However, they are not generally recommended in pregnancy as there is little information about how they might affect the unborn baby.


What are the risks of using a bisphosphonate in pregnancy?

Bisphosphonates are stored in bone and are thought to stay in the body for up to ten years. In theory, this means that a pregnancy occurring several years after bisphosphonate use could be exposed.

The risks are largely unknown. Only around 100 women taking bisphosphonates either before or during pregnancy have been studied. While bisphosphonates did not cause ill-effects in their babies, further research is required to make sure.


Are there any alternatives to using a bisphosphonate in pregnancy?

Switching drugs or stopping treatment may be an option. If you are planning a pregnancy, or become pregnant during or after bisphosphonate therapy, you should discuss options with your doctor.

No treatment

What if I prefer not to take a bisphosphonate during pregnancy?

Stopping a bisphosphonate may be an option if advised by a doctor.

Medicines will only be prescribed during pregnancy when necessary and a doctor will be happy to talk to you about any concerns.

Will I or my baby need extra monitoring?

As part of routine antenatal care, most women will be offered a detailed scan at around 20 weeks of pregnancy to check the baby’s development. Extra monitoring for major birth defects is not usually required. As the effects of bisphosphonates are largely unknown, some doctors might advise additional checks of the baby’s growth and wellbeing.

There have been a small number of reports of babies exposed in the womb to bisphosphonates having low calcium levels. The baby’s calcium level may therefore be checked after delivery with a blood test.

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

There is no evidence that a bisphosphonate used by the father can harm the baby through effects on the 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

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.