Plasma hypoxanthine and intraerythrocytic ATP in umbilical cord blood as markers of perinatal hypoxia

We determined blood pH, plasma hypoxanthine (Hx) and intraerythrocyte ATP (iATP) concentrations in umbilical cord blood from 20 normal newborn infants (10 delivered by the vaginal route and 10 by caesarean section) and in 18 newborns with clinical signs of perinatal asphyxia (9 with meconium stained amniotic fluid and 9 with fetal bradycardia). Blood pH was significantly lower in infants with clinical signs of perinatal asphyxia (p less than 0.01). Four newborns with meconium or bradycardia had pH values within normal control levels. Hx concentrations were lower in infants delivered by caesarean section with respect to normal infants born by the vaginal route (p less than 0.05). Newborns with meconium or fetal bradycardia showed Hx concentrations higher than normal newborns (p less than 0.01), but 2 infants with signs of perinatal hypoxia had Hx levels within the normal newborn range. All babies with meconium or bradycardia had an iATP concentration lower than control infants (p less than 0.01). These results indicate that: the pH and Hx determinations in the newborn may underestimate hypoxia and, that measurement of iATP may be useful parameters to asses perinatal hypoxia.