Postnatal Risk Factors

The origins of intellectual and developmental disorders can be genetic or the result of adverse events during the prenatal (before birth), perinatal (around the time of birth), or postnatal (after birth) periods. Organs and body systems undergo the most rapid development during the prenatal [Page 1279]period, and as a result, they are the most vulnerable to adverse events before birth. Development of the brain and senses can still be significantly affected by environmental events during and after birth and continues through childhood and adolescence. Postnatal exposures such as poverty and crime, parental factors, nutrition, and health account for an estimated 3 to 15% of all developmental disabilities. This entry describes the factors that occur around the time of or after birth that increase the likelihood ...