Aug 29, 2008

Study Suggests Water Disinfection Byproducts Pose No Harm to Pregnancy

New research shows disinfection byproducts at regulatory cutoff levels do not raise risk of premature birth or delivery of a small baby

New research shows that drinking water containing disinfection byproducts at regulatory cutoff levels does not appear to raise a pregnant woman's risk of delivering prematurely or delivering a small baby, Reuters reported.

Dr. Caroline S. Hoffman from the University of North Carolina at Chapel Hill and colleagues studied analyses involving more than 3800 pregnant women, and found no link between exposure to drinking water disinfection byproducts—in particular, total trihalomethanes (TTHMs), haloacetic acids, and total organic halides—and an increased probability of delivering a small "growth-restricted" baby or delivering a low-birth weight baby.

In the September 2008 issue of the journal Epidemiology, the researches note that previous studies that have suggested adverse pregnancy outcomes in women exposed to drinking water disinfection byproducts "are limited by poor exposure assessment."

The new study was funded in part by the U.S. Environmental Protection Agency. The researchers used improved exposure data to calculate the potential risks more accurately. They collected weekly or biweekly water samples at representative locations in the water distribution systems of three communities in the U.S., according to Reuters.

The results do not support a harmful effect of residential TTHM or haloacetic acid levels within the regulatory limits on fetal growth, according to the investigators. Also, none of the individual TTHM or haloacetic acid types was consistently associated with fetal growth restriction.

Hoffman and colleagues found that a possible association between TTHM and delivery of a small baby was evident only for average residential concentrations above the current regulatory standard.

Their research also provides evidence, they add, that exposure to high levels of these disinfection byproducts does not increase the likelihood of delivering preterm.