Advances in understanding the effects of in utero exposure to chemicals

The uterine environment in which a foetus develops is critical to infant, child, and adult health. Adverse intra-uterine environments have been linked to increased risk for neurobehavioral disorders and metabolic and cardiovascular disease. Rapid cell division, tissue growth, differentiation, and organization of major organs are all features rendering the developing foetus sensitive to insult from exogenous chemicals. Therefore, interest in measurement of developmental exposure to environmental chemicals during critical periods of foetal development has grown. However, determining the consequences of developmental exposure to toxic chemicals presents epidemiologists, toxicologists, and regulatory health authorities with numerous important challenges. Improvements in analytical methods have led to greater sensitivity and thus detection of chemical residues at far lower concentrations, yet the biological relevance of the documented exposure is often unknown and difficult to determine. Although the benefit of quantifying exposure during critical windows of development is well recognized, access to appropriate biological fluids at relevant periods of development continues to pose a challenge. Moreover, knowledge gaps in the toxicological data together with lack of mechanistic insight make interpretation difficult and challenge confidence in conclusions of the human health consequences. Herein, a brief overview of several important issues central to understanding the consequences of developmental exposure to environmental toxicants is considered.