Drinking water disinfection by-product exposure and fetal growth

Previous studies suggest that elevated exposure 10 drinking water disinfection by-products (DBPs)-in particular, total trihalomethanes (TTHMs-may lead to fetal growth restriction. We examined the effects of exposure to TTHMs, haloacetic acids, and total organic halide oil the probability of delivering small-for-gestational-age (SGA) infant and on birth weight al term. Methods: Women early fit pregnancy (: 12 weeks' gestation) or planning a pregnancy were enrolled in a prospective pregnancy study conducted in 3 US communities from 2000 through 2004. Weekly (or biweekly) water samples were collected at each site as well as individual-level participant data. Associations between DBP exposures (T-THMs, halolacetic acids. total organic halide) and fetal growth Were assessed Using log-binomial regression for SGA (it 1958) and linear regression For term birth weight (it - 1854). We conducted I Bayesian analysis to examine associations between individual DBP species and fetal growth. Results: Haloacetic acids and total organic halide were not associated with SGA or term birth weight. The probability of delivering an SGA infant was elevated when comparing women with an average third-trimester residential TTHM concentration >= 80 mu g/L to women with exposure <80 mu g/L (risk ratio = 2.0 [95% confidence interval 1.1-3.6]), but not when examining other exposure contrasts. Bayesian analyses did not support l Consistent association,growth although these analyses between any DBP species and fetal g were based oil small sample sizes. Conclusions: Our results do not suggest an adverse effect of haloacetic acid or total organic halide exposure oil fetal growth. All association ol'TTI-INI with SGA was seen only for average r sid tial concentrations above the current( extraordinary standard.