Neonatal depression and birth asphyxia in the low birthweight neonate.

In 392 low birthweight neonates, acidosis as evident from umbilical artery pH 7.1 or less was strongly associated with Apgar score 6 or lower at 1 minute. However, most cases that were depressed (Apgar score 6 or lower at 1 minute) were not acidotic. Neonatal depression was most strongly and directly correlated with gestational age. Neonatal depression and birth asphyxia are distinct entities.