Estimated Effects of Disinfection By-products on Preterm Birth in a Population Served by a Single Water Utility
2007

Effects of Disinfection By-products on Preterm Birth

Sample size: 37498 publication 10 minutes Evidence: moderate

Author Information

Author(s): Lewis Chad, Suffet Irwin H., Hoggatt Katherine, Ritz Beate

Primary Institution: University of California, Los Angeles

Hypothesis

We evaluated the association between drinking-water disinfection by-products and preterm births using improved exposure assessment and more appropriate analysis methods than used in prior studies.

Conclusion

The study suggests that high levels of trihalomethanes during the second trimester may reduce the risk of preterm births, while exposure in the last four weeks before delivery may increase the risk for mothers relying on government-funded prenatal care.

Supporting Evidence

  • Women exposed to high levels of TTHM during the second trimester had a reduced risk of preterm birth.
  • Women relying on government payment for prenatal care had an increased risk of preterm birth when exposed to high TTHM levels in the last four weeks of pregnancy.
  • The study population was large enough to examine the relation between preterm births and TTHM across different racial/ethnic and socioeconomic groups.

Takeaway

Drinking water disinfection by-products might help some babies be born on time, but they could also make it more likely for some moms to have their babies too early, especially if they don't have good healthcare.

Methodology

The study used vital record data from a diverse population in Massachusetts and employed proportional hazards regression to analyze the effects of trihalomethanes on preterm births.

Potential Biases

Potential selection bias may exist due to focusing only on live births and not accounting for fetal deaths.

Limitations

The study could not distinguish between various pathways of exposure and may have residual confounding due to lack of information on selected risk factors.

Participant Demographics

The study included a large, racially diverse population of mothers in Massachusetts.

Statistical Information

P-Value

p<0.05

Confidence Interval

95% CI, 0.95–1.35

Statistical Significance

p<0.05

Digital Object Identifier (DOI)

10.1289/ehp.9394

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