Total trihalomethanes in public drinking water supply and birth outcomes: a cross-sectional study.

Reproductive effects of long-term, low-dose exposure to disinfectant by-products have not been consistently documented in large populations despite the known toxicity of high exposures and the wide-spread occurrence of low concentrations in public drinking water. We investigated the effect of low-dose exposure to total trihalomethanes (TTHM) on birth weight and gestational term in New York State. All singleton live births from 1998 through 2003 in 62 counties in New York State were linked with public water supply (PWS) system boundaries based on mother's residential address on birth certificate.