The pH levels of a neonatal at his birth are an important factor in establishing the connection between events that occurred during the actual time of birth, to the risk of a significant morbidity development in the future. Gas values in cord blood are measurable and represent the condition of the fetus close to the time of birth. Their level is one of the essential criteria which are used to define acute hypoxic event during birth. As the oxygen supply to the fetus significantly disturbed, deficiency of oxygen in the tissues is growing. Therefore, the tissues begin to accumulate large amounts of acid and thereby developing fetal blood acidosis. Many works connected the presence of cord blood acidosis to development of neonatal cerebral palsy. According to the American Association of Obstetrics and Gynecology, cord blood gas sample is necessary when a prenatal event may be related (rightly or not) with negative neonatal outcome. This approach might be necessary when the case is legally controversial and there is a need to prove that umbilical cord gas values were normal at the prenatal period.