Exposure to drinking water trihalomethanes through different routes and low birth weight risk in genetically susceptible women

Abstract

Recent epidemiological studies have suggested that trihalomethanes (THM) exposures during pregnancy might impair fetal growth. However, the estimation of relationships of THM and low birth weight (LBW) relied on relatively crude exposure assessment not examining genetic susceptibility to environmental hazards. Methods: We performed an epidemiological study to examine the relationship between THM internal dose and the risk of LBW and term-LBW among genetically susceptible women in Kaunas, Lithuania. The study included 527 women. Residential history, water drinking, showering and bathing habits during pregnancy, and known risk factors for LBW, were measured with interview. Mothers were characterized for GSTM- and GSTT polymorphisms. Integrated exposure to THM was measured using THM concentration and ingested amount, bathing, and showering. We examined the relation of THM exposure to LBW and term-LBW with a multiple linear-regression models, adjusting for gestational age, maternal education, family status, body mass index, blood pressure, and parity. Results: We found a weak association of THM exposure during third trimester with term-LBW (OR: 3.69; 95% CI: 0.65–21.0) for the exposure level over median among women GSTM1-null genotype carriers; a statistically significant increase in risk LBW (OR: 3.89; 95% CI: 1.11–13.64), and no association between exposure and fetal growth among women GSTM1-present genotype carriers. However, a small number of adverse birth outcomes reduced the statistical significance of these results. Conclusion: The study data suggest a potentially impact relation between third trimester exposure to THM and fetal growth in genetically susceptible subjects.