You need to be logged in to see the full monograph.


Date of issue: January 2023, Version: 3.0

Sodium thiosulfate is an inorganic reducing agent used in commercial/industrial processes and as an antidote for cyanide poisoning.

There are no human pregnancy exposure data regarding the fetal effects of sodium thiosulfate exposure. The available animal data, although limited, have not demonstrated teratogenic effects for sodium thiosulfate. Improved maternal and fetal outcomes have been demonstrated when sodium thiosulfate was administered in the treatment of cyanogenic compound exposure in pregnant ewes.

If sodium thiosulfate is required in the management of cyanide poisoning during pregnancy, treatment should not be withheld on account of pregnancy.

As with all chemicals, unnecessary exposure to sodium thiosulfate should be avoided. Where occupational exposure is unavoidable, precautions should be taken to ensure that exposure is well within the recommended exposure limits and not associated with toxic symptoms.

Exposure to sodium thiosulfate 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.

Where exposure to cyanide has occurred in pregnancy, enhanced antenatal monitoring may be warranted and discussion with UKTIS is recommended in all cases.

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.