Prospective study of birth defects from
fetotoxic agents in the public water supply

The aim of this study is to assess whether there is an association between trihalomethane (THM) exposure, via the public water supply, and the prevalence of birth defects in Perth. The link between maternal exposure to DBPs and an elevated risk for a range of adverse reproductive outcomes is still inconclusive. A recent review on DBPs and birth defects concluded that further evidence is required; especially to study the effects of highly brominated public water supplies on adverse birth outcomes, and to overcome the limitations in exposure assessment of most existing studies. We seek to extend our findings from our retrospective record-based analysis to include collection of individual exposure and birth outcome data, along with contemporaneous water quality analysis. Our investigation will use a robust design: a prospective cohort study, and will focus on the relatively unstudied brominated forms of THMs. The results from this study will further inform the international debate about the relationship between levels of disinfection by-products in water and adverse health outcomes.

This study will use a prospective cohort design to assess the impact of THMs in a population of pregnant women residing in metropolitan Perth. Recruitment will run for a full 3 years (36 months) and will involve 5000 adult pregnant women seen by Obstetrician General Practitioners and Obstetric Ultrasound Specialists. A self-administered questionnaire has been developed to ascertain frequency and duration of water use (in relation to swimming and showering), the type and amount of water ingested (separated into cold and hot drinks), and other factors associated with reproductive outcomes. Subjects will be asked to consent to evaluation of the subsequent outcome of their pregnancy using routinely-collected obstetric and birth defect data. THMs will be tested in a range of distribution zones across Perth. Zones will be analysed seasonally over the course of the 36 month recruitment phase of the study, as well as the three months prior to commencing recruitment to ensure adequate collection of 1st trimester exposure data for all participants.

There remains ongoing controversy surrounding DBPs and adverse pregnancy outcomes. Public awareness about potential hazards in water supplies is increasing. High concentrations of brominated THMs are present in Australia; a potentially more teratogenic THM. The results of the study will inform national and international water contaminant research, and provide a sound basis for revising water quality standards.

This project is funded by the National Health and Medical Research Council (NHMRC) Project Grants scheme (2011-2014)

For further information, please contact Phil Weinstein