Perchlorate in Drinking Water During Pregnancy and Neonatal Thyroid Hormone Levels in California.
Steinmaus C, Miller MD, Smith AH.
J Occup Environ Med. 2010 Nov 30. [Epub ahead of print]
From the Office of Environmental Health Hazard Assessment, California Environmental Protection Agency, Oakland, Calif (Dr Steinmaus and Dr Miller), Division of Occupational and Environmental Medicine, University of California, San Francisco, Calif (Dr Steinmaus and Dr Miller), School of Public Health, University of California, Berkeley, Calif (Dr Steinmaus and Dr Smith).
Abstract
OBJECTIVE: To evaluate associations between maternal drinking water perchlorate exposure during pregnancy and newborn thyroid hormone levels.
METHODS: Elevation in thyroid stimulating hormone (TSH), which may reflect reduced thyroxin concentration, was assessed in 497,458 newborns in California in 1998. A total of 800 perchlorate water measurements were used to classify California communities as exposed (>5 μg/L) or unexposed. Results were stratified by age at TSH collection because of the normal postbirth TSH surge, and because water sources and perchlorate exposure can change soon after birth.
RESULTS: In TSH samples collected within 24 hours of birth, the odds ratio for a TSH greater than 25 μU/mL in exposed communities was 1.53 (P < 0.0001). After 24 hours, the odds ratio for a TSH more than the 95th percentile was 1.27 (P < 0.0001).
CONCLUSION: These findings suggest that perchlorate is associated with increased neonatal TSH levels.
