Effect of Intrauterine Growth Restriction on Cerebral Regional Oxygen Saturation in Preterm and Term Neonates during Immediate Postnatal Transition

Background: Intrauterine growth restriction (IUGR) is associated with adverse perinatal outcome. Affected fetuses commonly display typical blood flow redistribution towards the brain ("brain sparing"). Accordingly, increased cerebral oxygen saturation has been observed in IUGR neonates within the first days of life. Aim: The aim of our study was to assess cerebral oxygenation behavior during immediate neonatal transition in IUGR infants. Methods: This is a retrospective single-center observational cohort study. Cerebral regional oxygen saturation (crSO(2)) was measured with near-infrared spectroscopy in neonates during the first 15 min after birth. Neonates with IUGR (IUGR group) were matched for gestational age (+/- 1 week) and gender with neonates that were appropriate for gestational age (AGA). The AGA:IUGR matching ratio was 3:1. Arterial oxygen saturation (SpO(2)), heart rate (HR), crSO(2), and cerebral fractional tissue oxygen extraction (cFTOE) were compared between the groups. Results: Between August 2010 and October 2017, 45 neonates with IUGR were identified and matched to 135 AGA neonates. Mean gestational age was 33.1 +/- 3.0 weeks in the IUGR group and 33.5 +/- 2.7 weeks in the AGA group. Mean birth weight was 1,559 +/- 582 g in the IUGR group and 2,051 +/- 679 g in the AGA group. There was a significant group difference in crSO(2) beginning at 5 min and continuing for the rest of the observation time with higher crSO(2) values in the IUGR group (main effect group: p = 0.011; interaction time x group: p = 0.039). In cFTOE, a significant difference could be observed at 5-9 and 11-13 min with lower rates of oxygen extraction in the IUGR group (main effect group: p = 0.025; interaction time x group: p = 0.463). Concerning SpO(2) and HR, there was no significant difference between the IUGR and the AGA neonates. Conclusion: Neonates of the IUGR group did show significantly higher crSO(2) values and significantly lower cFTOE values already during immediate neonatal transition compared to the AGA group.