Drinking water and pregnancy outcome in central North Carolina: source, amount, and trihalomethane levels

Environ Health Perspect. 1995 Jun;103(6):592-6. doi: 10.1289/ehp.95103592.


In spite of the recognition of potentially toxic chemicals in chlorinated drinking water, few studies have evaluated reproductive health consequences of such exposure. Using data from a case-control study of miscarriage, preterm delivery, and low birth weight in central North Carolina, we evaluated risk associated with water source, amount, and trihalomethane (THM) concentration. Water source was not related to any of those pregnancy outcomes, but an increasing amount of ingested water was associated with decreased risks of all three outcomes (odds ratios around 1.5 for 0 glasses per day relative to 1-3 glasses per day, falling to 0.8 for 4+ glasses per day). THM concentration and dose (concentration x amount) were not related to pregnancy outcome, with the possible exception of an increased risk of miscarriage in the highest sextile of THM concentration (adjusted odds ratio = 2.8, 95% confidence interval = 1.1-2.7), which was not part of an overall dose-response gradient. These data do not indicate a strong association between chlorination by-products and adverse pregnancy outcome, but given the limited quality of our exposure assessment and the increased miscarriage risk in the highest exposure group, more refined evaluation is warranted.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Case-Control Studies
  • Chlorofluorocarbons, Methane / adverse effects*
  • Dose-Response Relationship, Drug
  • Evaluation Studies as Topic
  • Female
  • Fresh Water / chemistry*
  • Humans
  • North Carolina / epidemiology
  • Pregnancy
  • Pregnancy Outcome / epidemiology*
  • Risk Factors
  • Water Pollutants, Chemical / adverse effects*


  • Chlorofluorocarbons, Methane
  • Water Pollutants, Chemical