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Date of issue: March 2016
Version: 2

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.


Alendronic acid is a bisphosphonate licensed in adults for the treatment of postmenopausal osteoporosis and for the prophylaxis of glucocorticoid-induced osteoporosis. As alendronic acid is incorporated into bone, the terminal half-life is long (up to 10 years). Fetal exposure could therefore occur in pregnant women with a history of alendronic acid use prior to conception.

Animal studies have demonstrated that alendronic acid can be absorbed into the fetal skeleton and affect offspring incisor eruption.

The available human exposure data are highly limited, consisting of a single prospective cohort study and case series/reports which detail the outcomes of 28 women who used alendronic acid in the first trimester of pregnancy and 17 women who discontinued use up to six months prior to conception.

No evidence of an increased risk of congenital malformation is provided from this limited data. One study suggested an increased risk of spontaneous abortion, whilst also reporting a decreased median gestational age at delivery and a decreased median birth weight following alendronic acid exposure during pregnancy or up to six months prior to conception. However, the results of this study are likely to be confounded and therefore additional studies are required before conclusions can be provided.

Exposure to alendronic acid at any stage in pregnancy would not usually be regarded as medical grounds for termination of pregnancy or any additional fetal monitoring. However, other risk factors may be present in individual cases which may independently increase the risk of adverse pregnancy outcome. Clinicians are reminded of the importance of consideration of such factors when performing case-specific risk assessments.

This document is regularly reviewed and updated. Only use full UKTIS monographs downloaded directly from to be sure you are using the most up-to-date version. The summaries of these monographs are openly available on

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from or to ensure you are using the most up-to-date version.