The relation between perinatal conditions and developmental outcome in low birthweight infants. Comparison of two cohorts.

We have compared the relations between perinatal conditions and developmental outcomes at age four years for two cohorts of children with birthweights 2,300 g or less, who did not develop cerebral palsy--one from Southeastern Wisconsin (children born 1975-76) and the other from Copenhagen (children born 1980-82). We examined the general effects of parental education and socioeconomic status, the use of Cesarean section, the degree of prematurity and neonatal complications on outcome. The methods of latent path structural analysis were used to form two models among 15 latent variables: one for children from Copenhagen and a similar model for children from Wisconsin. The impact of parental education and socioeconomic status was somewhat greater in Wisconsin. Several neonatal complications were related to outcome in Wisconsin: the early condition of the infant, use of a respirator, pneumothorax, and anemia/apnea. The only neonatal complication with a significant relation to outcome in Copenhagen was pneumothorax and to a much lesser degree major germinal layer haemorrhage. The degree of prematurity per se had a greater impact in Copenhagen. The use of Cesarean section and mechanical ventilation in the smallest infants was much more frequent in Denmark, but no association could be shown between this increased use and improved developmental outcome.