The effect of water disinfection by-products on pregnancy outcomes in two southeastern US communities.

OBJECTIVE: To determine if exposure to disinfection by-products (DBPs) during gestation increases the risk of adverse birth outcomes, specifically term small for gestational age (SGA) birth, preterm birth (PTB), and very PTB (<32 weeks' gestation). METHODS: We used weekly measurements total trihalomethanes (TTHMs), five haloacetic acids (HAA5), and total organic halides (TOX) collected from two distribution systems to evaluate the associations between DBP concentrations and term SGA, PTB, and very PTB using logistic regression. RESULTS: We found no associations between DBPs and term-SGA. In the site with higher concentrations of bromine-containing DBPs, we found an association between TOX and PTB; this association was larger, though less precise, for very PTB. CONCLUSIONS: Our results do not support an association between TTHMs or HAA5 and the birth outcomes investigated, but an association was found between increased TOX and PTB.