One of the major goals of obstetricians is to prevent fetal asphyxia. Unfortunately, the commonly used clinical indicators (fetal heart rate monitoring, meconium staining of the amniotic fluid, and Apgar scores) do not have acceptable accuracy in establishing the presence of fetal asphyxia. These subjective assessments often overdiagnose fetal asphyxia and on occasion may fail to detect its presence. The only scientific, objective means of diagnosing fetal asphyxia at delivery is through umbilical blood acid-base studies. This test is convenient, noninvasive, and accurate. The routine use of umbilical blood acid-base studies is a major asset to the obstetric team in determining (1) the presence of asphyxia and its consequences, (2) the efficacy of interventions to prevent fetal asphyxia, and (3) the mechanisms responsible for fetal acidosis.