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Environmental Exposures Unlikely to Alter Thyroid Function of Pregnant Women, Fetuses

Released: 19-Sep-2012 9:00 AM EDT
Embargo expired: 20-Sep-2012 2:55 PM EDT
Source Newsroom: American Thyroid Association
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Citations 82nd ATA Annual Meeting

Newswise — Falls Church, Virginia. Sep. 20, 2012 – Exposures to perchlorate (ClO4), a compound found at low levels in the environment, and thiocyanate (SCN), a compound found in cigarette smoke and some foods, is unlikely to alter thyroid function in pregnant women and fetuses, according to new data presented at the 82nd Annual Meeting of the American Thyroid Association (ATA) in Québec City, Québec, Canada.

“The developing fetus is reliant on maternal iodine for thyroid hormone production for normal neurodevelopment. Environmental exposures to ClO4 and SCN exposures during pregnancy could potentially decrease thyroidal iodine uptake in the mother and/or her fetus and subsequent thyroid hormone synthesis,” said Elizabeth Pearce, MD, of Boston Medical Center, Program Co-Chair of the ATA Annual Meeting and co-author of the study.

Led by Angela Leung at the Boston University School of Medicine in Boston, Mass., a team of researchers thus sought to determine for the first time the urinary CIO4 and SCN concentrations in Canada. They recruited 150 pregnant women from four low-risk antenatal outpatient clinics in Toronto, Canada, to provide a spot urine sample for the measurement of both compounds. The women were in their second and third trimesters, primarily Caucasian, well educated, and relatively affluent. The median urinary CIO4 concentration was 3.2 lg/L (range, 0.5–48.1 lg/L), and the median urinary SCN concentration was 351lg/L (range, 28–1195lg/L). These women were iodine sufficient (median urinary iodine concentration 227.1lg/L), as was previously presented at the 2011 American Thyroid Association meeting.

Researchers noted that low levels of both CIO4 and SCN are comparable to those previously reported by in iodine-deficient and sufficient pregnant women from Wales, Italy, Argentina, and the United States where environmental exposures had no effect on maternal thyroid function.

About the ATA Annual Meeting 

The 82nd Annual Meeting of the American Thyroid Association is held Sept. 19-23, in Québec City, Québec, Canada. This four-day creative and innovative scientific program, chaired by Elizabeth Pearce, MD, Boston Medical Center, and Douglas Forrest, PhD, National Institute of Diabetes and Digestive and Kidney Diseases, carefully balances clinical and basic science sessions on the latest advances in thyroidology. The ATA meeting is designed to offer continuing education for endocrinologists, internists, surgeons, basic scientists, nuclear medicine scientists, pathologists, endocrine fellows and nurses, physician assistants and other health care professionals. Visit for more information.

About the ATA 

The American Thyroid Association (ATA) is the leading worldwide organization dedicated to the advancement, understanding, prevention, diagnosis and treatment of thyroid disorders and thyroid cancer. ATA is an international individual membership organization with over 1,600 members from 43 countries around the world. Celebrating its 89th anniversary, ATA delivers its mission through several key endeavors: the publication of highly regarded monthly journals, THYROID, Clinical Thyroidology and Clinical Thyroidology for Patients; annual scientific meetings; biennial clinical and research symposia; research grant programs for young investigators, support of online professional, public and patient educational programs through; and the development of guidelines for clinical management of thyroid disease. Visit for more information.

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