Umbilical artery acid-base status in the preterm infant

It is becoming increasingly apparent that Apgar scores are generally lower in otherwise uncomplicated preterm newborns than in term newborns. However, there is little information regarding normal values for umbilical artery blood gas measurements in the preterm infant. The present study included 77 otherwise uncomplicated preterm infants and 1292 uncomplicated term infants. Although preterm infants did have significantly lower 1- and 5-minute Apgar scores, there was no significant difference in the frequency of acidemia (umbilical artery pH below 7.20). The mean pH was 7.29 in preterm infants and 7.28 in term infants. Mean values for pCO₂, pO₂, HCO₃, and base deficit were similar in each group. There were no significant differences in umbilical artery blood gas values in the 77 preterm infants according to birth weight groups. Umbilical cord blood acid-base determination may prove a useful adjunct in assessing the condition of the newborn preterm infant.