Umbilical cord blood gas analysis

Umbilical blood sampling at delivery has emerged as the most objective meas urement of utero placental function and fetal oxygenation/acid-base status at birth. Most depressed newborns completely normal umbilical cord blood ga s values. In contrast to the poor specificity of fetal heart rate monitorin g and Apgar scores, umbilical cord blood gas analysis defines the exact aci d-base balance and differentiates perinatal asphyxia from other conditions leading to immediate newborn depression and adverse neurologic sequelae. Th is article discusses normal cord blood gas values, pertinent acid-base phys iology, factors affecting these values, and the advantages of universal ver sus selective sampling strategies.