Oxygen saturation profile in late-preterm and term infants: a prospective cohort study

OBJECTIVE: To determine oxygen saturation profile over 6 h monitoring period in healthy late-preterm and term neonates during the first 48 h of age, and to assess the impact of gestational age, birth weight and method of delivery on this profile. STUDY DESIGN: Prospective cohort study of measurement of SpO(2) over 6 h in 20 late-preterm (35 to 36 weeks gestation) and 40 term infants within 12 to 48 h of birth was conducted. Infants with cardiorespiratory symptoms or need for cardiorespiratory support at birth were excluded. Percentage time spent at SpO(2) >90% and <= 90% was calculated by gestational age and birth weight. RESULT: Late-preterm infants and infants born weighing <2.5 kg spent approximately 7% of the time at SpO(2) <= 90%; this time decreased as gestational age and birth weight increased. Time at SpO(2) >90% was significantly different between late-preterm and term infants (93% (5%) vs 96% (3%); P = 0.002). Time at SpO(2) >90% was not significantly different between males and females (95% (5%) vs 95% (4%), both n = 30; P = 0.72) or between vaginal births and cesarean births (95% (4%), n=32, vs 95% (4%), n = 28; P =0.39). Cumulative time with SpO(2) <90 was mean (s.d.) of 25 (18) in preterm vs 13 (10) min in term infants. CONCLUSION: Over a 6-h period healthy late-preterm and term infants spent significant time at SpO(2) <= 90%. Lower gestation and lower birth weight were associated with higher time at SpO(2) <= 90%.