Polybrominated diphenyl ethers (PBDEs) and perfluorocarbons (PFC) are chemicals that are used as flame retardants and surfactants in a wide variety of consumer products. In animal studies, both chemical groups have been shown to have toxic effects on the thyroid and have the potential to affect fetal brain development. A small but growing body of evidence suggests similar thyroid effects may occur in humans; however, the links between these chemicals and thyroid disruption in early pregnancy, the most critical window of exposure, are still unclear. The specific effects of prenatal PBDE and PFC exposures on neurodevelopment in humans are largely unknown. Disturbingly, both chemicals are present in the blood of the entire Canadian population, including children and newborns, and the most important sources of these chemicals are poorly understood. The post-doctoral research of Dr. Glenys Webster will help fill these gaps by 1) identifying the main sources of PBDEs in maternal blood, 2) exploring whether maternal PBDE levels are associated with maternal thyroid hormone levels in early pregnancy, a time when thyroid hormones play a critical role in fetal brain development, and 3) examining the relationships between maternal PBDE and PFC levels and neurodevelopmental outcomes in one- to three-year-old children, as measured by cognition, motor function and behavior. Dr. Webster's work will use data from two existing pregnancy cohorts in Vancouver and Cincinnati, and will link the sources of chemical exposure to chemical levels in blood to maternal thyroid effects to child neurodevelopmental effects, all within the same study populations. Understanding the public health implications of population-wide exposures to PBDEs and PFCs will provide key information for ongoing risk assessment and risk management strategies in Canada and will support the development of effective chemical regulation policies to protect public health.