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Date of issue: September 2023, Version: 4.0

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A corresponding patient information leaflet on EXPOSURE TO BOTULINUM TOXIN IN PREGNANCY is available.

Botulinum toxin type A (BTX-A) is licensed for the treatment of blepharospasm, hemifacial spasm, idiopathic cervical dystonia, focal spasticity, bladder dysfunction, the prophylaxis of headaches in adults with severe migraine, and in the management of severe axial hyperhidrosis. BTX-A is also used in aesthetic dermatology to temporarily improve the appearance of facial lines.

Botulinum toxin is produced by the bacterium Clostridium botulinum and is the cause of botulism, a potentially severe illness that can lead to paralysis and acute respiratory failure.

There are limited data on which to base an assessment of the safety of BTX-A in human pregnancy. Animal studies of exposure to high doses of BTX-A have demonstrated teratogenic risk. Data from human pregnancies exposed to Clostridium botulinum infection or to BTX-A do not raise concern of adverse pregnancy outcomes but are too limited to formally exclude any increase in risk. It is noteworthy that significant systemic exposure to BTX-A is not expected when it is administered as per the manufacturer’s instructions; fetal risk is therefore expected to be low in the absence of systemic side-effects.

If botulism infection is suspected, due to the potential severity of the illness, treatment during pregnancy should be the same as for the non-pregnant patient. Data on maternal treatment with botulinum antitoxin are very limited but have not shown evidence of fetal harm, and where clinically indicated, treatment with the antidote should not be withheld on account of pregnancy. Additional fetal monitoring may be warranted in cases of maternal botulism, particularly if exposure is associated with maternal hypoxia. Discussion with UKTIS is recommended in all cases.

 Use of BTX-A during pregnancy should usually be reserved for therapeutic indications where there is no suitable alternative treatment. However, prescribers should consider that use of BTX-A can, in some circumstances (e.g. for headache prophylaxis), avoid systemic drug exposure and may therefore be the option associated with lowest potential risk. It is pragmatically recommended that use of BTX-A for cosmetic indications during pregnancy should be avoided. Pregnant women with inadvertent exposure to BTX-A can be reassured that, in the absence of systemic side-effects, the risk to the fetus is low. 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 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 NHS health care professionals who are logged in.

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 to ensure you are using the most up-to-date version.