Behavior at 10 and 13 years of age for children with low birth weight.

This study was based on data from a longitudinal research program. The cohort consisted of 874 normal children in an entire school grade in a Swedish community. The aim of the study was to investigate the relation between birth weight and behavior at school, for all children and for each sex separately. The results identified specific aspects of behaviour disorder significantly related to low birth weight (LBW) for children at the age of 10 but not at the age of 13. When the sexes were separated, there were no relations between birth weight and deviant behaviour for boys of low birth weight as compared to boys of normal birth weight, while girls of low birth weight showed specific behavioural disorders at age 10 as compared to girls of normal birth weight. For girls reared in families of low parental socioeconomic status, aggressiveness and motor restlessness at age 10 but not at age 13 was also present. Further analyses showed that girls born small-for-gestational age showed lack of school motivation and concentration difficulties both at age 10 and age 13.