Outcome of very low birth weight infants in industrialized countries: 1947-1987.

Neonatal intensive care has led to a progressive improvement in the survival of very low birth weight (VLBW, < 1,500 g) infants. However, it has not been established whether there has been a simultaneous increase or decrease in the prevalence of handicapping conditions in this group of children. To explore this question, a meta-analysis was performed using outcome data of 32 developmental studies of VLBW infants born in industrialized countries between 1947 and 1987. The authors' results show that the proportion of VLBW infants who survived and had an intact outcome progressively increased between 1947 and 1987--from 147 per 1,000 live births in the period 1947-1965 to 498 per 1,000 in the period 1980-1987 (p < 0.01). The prevalence of major handicapping conditions for the subset of VLBW infants who weighed < 1,000 g at birth increased, resulting from the increasing survival rates. However, the prevalence of major handicapping conditions among all children with VLBW decreased from 147 per 1,000 live births in 1947-1965 to 45 per 1,000 in 1980-1987 (p = 0.02). The authors' meta-analysis suggests that improved survival of VLBW infants has not been accompanied by an increase, but more likely a decrease, in the prevalence of handicapping conditions in this birth weight group.