Exposure to trihalomethanes in drinking water and small-for-gestational-age births

Richard J. Summerhayes, Geoffrey Morgan, Howard P. Edwards, Douglas Lincoln, Arul Earnest, Bayzidur Rahman, John R. Beard

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11 Citations (Scopus)

Abstract

Background: Trihalomethanes in drinking water have been associated with higher occurrence of small-for-gestational-age (SGA) births, although results have been inconsistent. Method: We geocoded residential address for mother of live, singleton, term births to 33 water distribution systems in a large metropolitan area of New South Wales, Australia (314,982 births between 1998 and 2004) and classified births into <10th percentile and 10 percentile of weight for gestational age. Mean trihalomethane exposure was estimated by trimester and for the entire pregnancy based on monthly sampling in each of the 33 water distribution systems. We estimated the relative risk (RR) of SGA for exposure to trihalomethanes using log-binomial regression adjusting for confounding. Results: SGA births increased with mothers third-trimester exposure to chloroform (RR=1.04 [95% confidence interval=1.02-1.06], across an interquartile range [IQR]=25 μg/L) and bromodichloromethane (1.02 [1.01-1.04], 5 μg/L). Larger associations were found for SGA less than third percentile. Smoking modified the effects of trihalomethane exposure, with generally larger associations in births to nonsmoking mother and weaker or protective associations in births to smoking mothers. Conclusions: Mothers exposures during pregnancy to total trihalomethane as well as to chloroform and bromodichloromethane were associated with SGA. These associations were modified by maternal smoking during pregnancy.

Original languageEnglish
Pages (from-to)15-22
Number of pages8
JournalEpidemiology
Volume23
Issue number1
DOIs
Publication statusPublished - Jan 2012
Externally publishedYes

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