Drinking water chlorination and adverse birth outcomes in Taiwan.

Chlorination has been the major strategy for the disinfection of drinking water in Taiwan. The use of chlorinated water has been hypothesized to lead to several adverse birth outcomes, including low birth weight and preterm delivery. We have performed a study to examine the relationship between the use of chlorinated water and adverse birth outcomes in Taiwan. The study areas included 113 "chlorinating municipalities" (CHMs) (which were defined as municipalities in which more than 95% of the municipality population was served by chlorinated water) and 15 "nonchlorinating municipalities" (NCHMs) (defined as municipalities in which less than 5% of the municipality population was served by chlorinated water). The study population comprised 182,796 women residing in the 128 municipalities who had a first parity singleton birth between 1 January 1994 and 31 December 1996, and for which complete information on maternal age, education, gestational age, birth weight, and sex of the baby were available The results of this study suggest that there was an association between the consumption of chlorinated drinking water and the risk of preterm delivery.