Umbilical cord blood acid-base state: what is normal?

Normal, vigorous newborns may exhibit a large range of blood acid-base levels. Researchers obtained umbilical cord blood acid-base values and blood gases from 16,000 newborns. Most (94%) were vigorous newborns, defined as those with Apgar scores of seven or higher five minutes after birth. The average blood pH for vigorous newborns was 7.26. Acid-base values that are more than two standard deviations away from this average represent abnormal values. Normal acid-base values range from 2.5 to 97.5th percentiles. Abnormal acid-base values in a newborn can lead to neurologic impairment.