Health assessment of exposure to developmental toxicants

The U.S. EPA has taken an important step in developing these guidelines, the first of their kind. They more precisely delineate the hazard identification process and the factors important in supporting risk decisions for developmental toxicants than does any other document. Unfortunately, however, more precise estimates of risk are hampered by our lack of understanding of a number of factors, including the biological mechanisms underlying developmental toxicity, intra/interspecies differences, the influence of maternal effects on the dose-response curve, the likelihood of thresholds for certain of these end points, and the appropriate quantitative models for dose-response data and for low-dose extrapolation. To this extent, the Agency is supporting and conducting a number of investigations which will hopefully further our knowledge and improve our ability to assess risks for the developing human. The guidelines will be updated as such information becomes available.