Aims: To study the normal levels of oxygen saturation (SpO(2)) in healthy newborns during the first 24 h of life and the possible relationship to birth weight and mode of delivery.
Methods: SpO(2) was measured by pulse oximetry on one occasion between 2 and 24 h after birth in 6805 asymptomatic newborns with gestational age > or =34 weeks and birth weight > or =2500 g.
Results: The average SpO(2) for all children was 98.0% (SD 1.4). SpO(2) was negatively related to birth weight and ranged from 98.2% (1.4) in children with birth weight 2750-2999 g to 97.6% (1.3) in children weighing >4500 g (P<0.001). No relationship exists between SpO(2) and gestational age or gender when correcting for birth weight. SpO(2) was independently related to mode of delivery, with higher levels in children born by cesarean section (98.3%; 1.3) than by vaginal delivery (98.0; 1.4; P<0.001). There was no relationship between SpO(2) and the interval from delivery to measurement.
Conclusions: In healthy newborns, levels of SpO(2) measured between 2 and 24 h of life are negatively related to birth weight and related to mode of delivery. However, the variation was within a small range and probably has few implications for the routine use of SpO(2) in newborns.