Perchlorate in drinking water during pregnancy and neonatal thyroid hormone levels in California.

摘要

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 mug/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 muU/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.