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James et al. reported in 1958 that gas analysis of blood samples obtained from a clamped umbilical cord could reflect fetal hypoxia.[1] Since then, cord blood gas analysis has become widely performed to objectively determine the fetal metabolic condition at the time of delivery when umbilical circulation stops.[2] Multiple studies showed that this analysis, when combined with other neonatal factors, can help identify infants at risk for neonatal encephalopathy, which is vital for the early initiation of neuroprotective therapeutic strategies.[3]

Cord blood gas analysis per se does not have any complications. However, a potential medico-legal concern may arise in centers practicing universal sampling when an abnormally low pH is found and documented in the medical record of vigorous newborns.[26] Although studies found that isolated acidosis in the absence of any other abnormal clinical finding at birth is a poor predictor of neonatal outcomes, practitioners may prefer in this case to repeat a blood gas analysis one to two hours after birth to document a “normal” pH.