Prenatal and Perinatal Factors in the Etiology of Autism

Abstract

This paper will review studies on prenatal and perinatal factors and the etiology of autism. It will focus on whether identified risk factors have been consistent from report to report, the extent to which identified risk factors are likely to be causal, and the extent to which identification of these factors can contribute to the development of strategies for the prevention of autism. Autism is one of a group of disorders often described as the developmental disabilities. Other disorders in this group are mental retardation, cerebral palsy, epilepsy, and learning disorders. Like these other disorders, autism is delineated by a set of observable dysfunctions and to some extent also by a shared natural history. Like these other disorders, autism is not a disease in the sense of having known biologic markers or known major etiologic factors in common. It is probable that autism is not the result of a single etiologic factor. Before examining the literature on autism, it may be useful to consider briefly what is known about maternal, pregnancy, and birth factors in the other developmental disabilities. EXPERIENCE WITH OTHER DEVELOPMENTAL DISABILITIES Contrary to expectations based on a hypothetical "continuum of reproductive causality," different developmental disabilities often have different major predictors. For example, the major known predictors of mental retardation and learning disorders are family characteristics such as educational level of the parents and measures of socioeconomic status.1,2 These characteristics are not important risk factors for cerebral palsy3 or epilepsy.4,5 Low birth weight is related to cerebral palsy but not to epilepsy in persons without cerebral palsy.6