Pulse oximetry saturations in the first 6 hours of life in normal term infants.

The pulse oximetry saturation values and the average percentage of time that normal newborns spend at different saturation ranges in the first 6 hours of life were determined in a cross-sectional study. Pulse oximetry saturation values were measured for a single 20-minute period in 101 normal term newborns between 20 minutes and 6 hours of age. The 25th percentile saturation values in the first postnatal hour (range 91%-100%) were lower than those from the second postnatal hour (range 96%-100%) onward. There was no significant difference between the 50th percentile (range 96%-100%) and the 75th percentile (range 97%-100%) saturation values in all postnatal hours. The babies spent a majority of time with saturations > or = 96% in all postnatal hours. A newborn more than 20 minutes old who does not achieve a pulse oximetry saturation value of 96% over several minutes of observation may need evaluation or continuous monitoring.