Association between gestational and environmental events and central nervous system function in 7-year-old children.

The prevalence of variables frequently associated with low birthweight was compared in samples of low-birthweight (LBW) infants and normal-birthweight infants (single births of the white race) drawn from the Boston component of the Collaborative Perinatal Research Project. Then the association between these exposure variables and central nervous system function at 7 years was examined in the LBW infants. Finally the interrelationships of the five variables having the strongest association with abnormal or suspect CNS function were examined with regard to their joint predictive utility. A high-risk subgroup (10%) of the total LBW group having a greater than 50:50 chance of falling into an adverse category at age 7 was identified by various combinations of the factors: gestational age of 33 weeks or less, premature rupture of membranes, low Apgar score, and respiratory distress. Small subgroups thus defined should receive special attention in follow-up, particularly in relation to the new regional perinatal care centers. They might also be selected for special study of the mechanisms of interference with central nervous system development. In a population of 7-year-old children with abnormal or suspect CNS function as defined by the protocol of this study, 80% will have a history of normal birthweight.