The risk of neonatal death and respiratory distress syndrome in relation to birth weight of preterm infants.

The aim of this study was to determine the risk of respiratory distress syndrome (RDS) and neonatal death (NND) in relation to birth weight in preterm neonates. A group of 255 singleton preterm neonates born at 22-36 weeks were examined. The mean birth weight for each gestational week was estimated from a fitted curve. Each birth weight was recalculated as a multiple of the mean. This approach allowed description of a range of birth weight for the whole population of preterm infants. As expected, the incidence of neonatal death and respiratory distress syndrome was higher among the less mature infants. However, there were no significant differences in outcome (NND, severe RDS) between infants whose birth weight was above or below the mean for gestational age, and no excess of "growth retardation" (birth weight below the 5th centile) in babies with NND or RDS. We conclude that, in our population, the risk of RDS and neonatal death does not appear to be related to the birth weight of preterm neonates but is, of course, related to gestational age.