Oxygen saturation trends immediately after birth.

OBJECTIVE To describe the changes in oxygen saturation (SpO2) in healthy infants during the first 10 minutes of life. STUDY DESIGN In this observational study, infants > or = 35 weeks gestation at birth who did not require supplemental oxygen had continuous recordings taken of the preductal SpO2 over the first 10 minutes of life. RESULTS A total of 115 infants were analyzed. On average, infants delivered by cesarean delivery had a 3% lower SpO2 than infants delivered by vaginal delivery (95% confidence interval [CI] = -5.8 to -0.7; P = .01). Infants born by cesarean delivery also took longer (risk ratio, 1.79) to reach a stable SpO2 > or = 85% (95% CI = 1.02 to 3.14; P = .04). At 5 minutes of age, median SpO2 values (interquartile range) were 87% (80% to 95%) for infants delivered vaginally and 81% (75% to 83%) for those delivered through cesarean section. The median SpO2 did not reach 90% until 8 minutes of age in either group. CONCLUSIONS The process of transitioning to a normal postnatal oxygen saturation requires more than 5 minutes in healthy newborns breathing room air.