Thallium poisoning during pregnancy: A case report and comprehensive literature review

Background: Thallium salts were once used to treat a variety of disorders s uch as tuberculosis, sexually transmitted diseases, and ringworm of the sca lp. Although the clinical manifestations and treatment of patients with tha llium poisoning are well characterized, little information is available on the outcome of pregnancy in thallium-poisoned women. A case of thallium poi soning that began during the first trimester of pregnancy and resulted in f etal demise is reported. Methods: An extensive literature search identified reported cases of thallium poisoning during pregnancy from 1903 until the present time. All articles were obtained, translated, and abstracted using a standardized data collection form. References were hand-searched and abst racted to identify additional cases. Results: From a total of 25 cases iden tified, only 18 met satisfactory criteria for inclusion. Five exposures occ urred during the first trimester, 5 during the second trimester, and 8 duri ng the third trimester. Mothers developed classic signs and symptoms of tha llium poisoning. Summary of these cases demonstrates a range of fetal effec ts from severe toxicity with residual sequelae to outwardly normal developm ent. Interestingly, some newborns appeared normal despite severe maternal t oxicity. The only consistent effect identified was a trend toward prematuri ty and low birth weight in children exposed during early gestation. Conclus ions: These cases document the transfer of thallium both across the placent a and in breast milk. Insufficient data are available to evaluate prognosti c markers of fetal outcome, or the risks and benefits of various treatment regimens in pregnant patients with thallium poisoning.