Implications of the use of neonatal birth weight, growth, viability, and survival data for predicting developmental neurotoxicity: a survey of the literature.

Current screening strategies for developmental neurotoxicants emphasize extensive behavioral and histological examination of the nervous system of maternally exposed offspring. In an ongoing effort to identify more rapid screening techniques which accurately predict developmental neurotoxicity, we conducted a literature review to investigate the suggestion that the Chernoff/Kavlock assay may adequately identify developmental neurotoxicants as well as developmental toxicants (58). We included information on a broad range of chemical classes including: pesticides, heavy metals, solvents, antiproliferative agents, and neuroactive drugs. For each chemical/agent, we recorded evidence of developmental neurotoxicity, teratological malformations of the nervous system, and associated information on the effects of that chemical on birth weight, growth, fetal viability, and/or neonatal survival (neonatal endpoints included in the Chernoff/Kavlock assay). Although complete Chernoff/Kavlock data were not always available, our results indicate that only 65% of developmental neurotoxicants affected at least one of the neonatal endpoints in the assay. Based on these results, we believe that reliance on the Chernoff/Kavlock assay as a primary developmental neurotoxicity screen could lead to a number of "false negatives" in hazard identification studies, and this assay should not be used to replace more comprehensive developmental neurotoxicity screening procedures.