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(Date of issue: November 2015, Version: 1.2)

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.


Thallium is an odourless, colourless and tasteless heavy metal formerly used in rodenticides, insecticides, fireworks, hair removers, and medically in the treatment of skin infections and tuberculosis.  Thallium is currently used in the manufacture of optical and electrical equipment, in jewellery manufacture, and in medical imaging (radioactive thallium-201).

Due to limited human pregnancy exposure data, it is not currently possible to offer an evidence-based insight into the risk maternal thallium exposure poses to the developing fetus.  Symptoms of neonatal thallium-related toxicity (including alopecia, dermal effects and failure to thrive) have been reported after thallium poisoning in later pregnancy in a small number of published cases.  Prematurity has also been reported after poisoning in early and late pregnancy.

Maternal toxicity after thallium exposure is likely to be a major determinant of risk to the fetus.  Owing to the severity of complications associated with thallium poisoning, treatment of the pregnant patient should be the same as for the non-pregnant patient.  If an antidote is indicated for treatment of maternal poisoning this should not be withheld on account of pregnancy.  For current guidelines on the management of thallium poisoning in pregnancy readers are advised to consult TOXBASE or contact UKTIS.

Where exposure to thallium has occurred, whether or not there is associated maternal toxicity, enhanced fetal monitoring (including monitoring fetal growth) may be warranted.  Discussion with UKTIS is recommended.

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

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 www.toxbase.org.

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 TOXBASE.org or UKTIS.org to ensure you are using the most up-to-date version.