DRINKING-WATER AND PREGNANCY OUTCOME IN CENTRAL NORTH-CAROLINA - SOURCE, AMOUNT, AND TRIHALOMETHANE LEVELS

In spite of the recognition of potentially toxic chemicals in chlorina ted drinking water few studies have evaluated reproductive health cons equences of such exposure. Using data from a case-control study of mis carriage, preterm delivery, and low birth; weight in central North Car olina, we evaluated risk associated with water source, amount, and tri halomethane (THM) concentration. Water source was not related to any o f those pregnancy outcomes, but an increasing amount of ingested water was associated with decreased risks of all three outcomes (odds ratio s around 1.5 for 0 glasses per day relative to 1-3 glasses per day, fa lling to 0.8 for 4+ glasses per day). THM concentration and dose (conc entration x amount) were not related to pregnancy outcome, with the po ssible exception of an increased risk of miscarriage in the highest se xtile of THM concentration (adjusted odds ratio = 2.8, 95% confidence interval = 1.1-2.7), which was nor part of an overall dose-response gr adient. These data do not indicate a strong association between chlori nation by-products and adverse pregnancy outcome, but given the limite d quality of our exposure assessment and the increased miscarriage ris k in the highest exposure group, more refined evaluation is warranted.