Perinatal toxicology: its recognition and fundamentals.

Perinatal toxicology is the study of aberrant or toxic responses to environmental agents when exposure occurs from conception through the neonatal period. The current increased interest in perinatal toxicology reflects the concern of both society and the individual in the resultant deficits induced by exposure to agents in the workplace, home, environment and by therapeutic intervention during early development. Not only is differentiation during organogenesis (the first eight weeks in human gestation) a highly susceptible period to the induction of malformations, but the fetal/neonatal developmental phases are just as sensitive for certain developmental deficits. Long-term postnatal evaluations are in most instances critical for the documentation of fetal/neonatal functional defects, which include carcinogenesis, behavioral impairment, endocrine and immune dysfunction. Ethylnitrosourea, estrogens (diethylstilbestrol), and cadmium are discussed in relationship to specificity of their fetal effects, long-term follow-up, and possible mechanisms of toxic action.