Relation of trihalomethane concentrations in public water supplies to stillbirth and birth weight in three water regions in England

Environ Health Perspect. 2005 Feb;113(2):225-32. doi: 10.1289/ehp.7111.


We investigated the association between total trihalomethanes (TTHMs) and risk of stillbirth and low and very low birth weight in three water regions in England, 1992-1998; associations with individual trihalomethanes (THMs) were also examined. Modeled estimates of quarterly TTHM concentrations in water zones, categorized as low (< 30 microg/L), medium (30-59 microg/L), or high (> or = 60 microg/L), were linked to approximately 1 million routine birth and stillbirth records using maternal residence at time of birth. In one region, where there was a positive socioeconomic deprivation gradient across exposure categories, there was also a positive, significant association of TTHM with risk of stillbirth and low and very low birth weight. Overall summary estimates across the three regions using a random-effects model to allow for between-region heterogeneity in exposure effects showed small excess risks in areas with high TTHM concentrations for stillbirths [odds ratio (OR) = 1.11; 95% confidence interval (CI), 1.00-1.23), low birth weight (OR = 1.09; 95% CI, 0.93-1.27), and very low birth weight (OR = 1.05; 95% CI, 0.82-1.34). Among the individual THMs, chloroform showed a similar pattern of risk as TTHM, but no association was found with concentrations of bromodichloromethane or total brominated THMs. Our findings overall suggest a significant association of stillbirths with maternal residence in areas with high TTHM exposure. Further work is needed looking at cause-specific stillbirths and effects of other disinfection by-products and to help differentiate between alternative (noncausal) explanations and those that may derive from the water supply.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • England / epidemiology
  • Female
  • Humans
  • Infant, Low Birth Weight
  • Infant, Newborn
  • Infant, Very Low Birth Weight
  • Maternal Exposure*
  • Odds Ratio
  • Pregnancy
  • Pregnancy Outcome / epidemiology*
  • Trihalomethanes* / analysis
  • Water Pollutants, Chemical* / analysis
  • Water Purification
  • Water Supply / analysis


  • Trihalomethanes
  • Water Pollutants, Chemical