Fetal hemoglobin (HbF) has a higher affinity to oxygen than adult hemoglobin, allowing for a slower oxygen transfer to peripheral tissue, creating a microenvironment conducive to adequate fetal development in utero . However, most preterm infants receive packed red blood cell transfusions from adult donors leading to a drastic nonphysiological descent of circulating HbF. We hypothesized that this drop could enhance oxygen delivery to peripheral tissues generating a hyperoxic pro-oxidant environment. To investigate this, we assessed differences in oxidative stress biomarkers determined in urine samples in a cohort of 56 preterm infants born <32 weeks' gestation. Median oxidative stress biomarkers were compared between patients with circulating HbF above or below median HbF levels using Wilcoxon rank sum test. Oxidative stress biomarkers were significantly higher in the group of patients with lower levels of HbF. This study provides the initial evidence indicating elevated levels of oxidative stress biomarkers in preterm neonates with lower HbF levels. Based on the results, we hypothesize that HbF may contribute to preventing free radical-associated conditions during the newborn period. Antioxid. Redox Signal. 40, 453–459.

The fetal-to-neonatal transition poses an extraordinary challenge for extremely low birth weight (ELBW) infants, and postnatal stabilization in the delivery room (DR) remains challenging. The initiation of air respiration and the establishment of a functional residual capacity are essential and often require ventilatory support and oxygen supplementation. In recent years, there has been a tendency towards the soft-landing strategy and, subsequently, non-invasive positive pressure ventilation has been generally recommended by international guidelines as the first option for stabilizing ELBW in the delivery room. On the other hand, supplementation with oxygen is another cornerstone of the postnatal stabilization of ELBW infants. To date, the conundrum concerning the optimal initial inspired fraction of oxygen, target saturations in the first golden minutes, and oxygen titration to achieve desired stability saturation and heart rate values has not yet been solved. Moreover, the retardation of cord clamping together with the initiation of ventilation with the patent cord (physiologic-based cord clamping) have added additional complexity to this puzzle. In the present review, we critically address these relevant topics related to fetal-to-neonatal transitional respiratory physiology, ventilatory stabilization, and oxygenation of ELBW infants in the delivery room based on current evidence and the most recent guidelines for newborn stabilization.

Immediate Kangaroo Mother Care (iKMC) after delivery and delayed cord clamping (DCC), both improve cardiorespiratory stability in newborns. This prospective observational study included 96 moderate to late preterm (MLPT) neonates. Preductal pulse oximetry (SpO₂) and heart rate (HR) were recorded during the first 10 min after birth. Neonates who received iKMC and DCC were compared to those who did not receive iKMC. iKMC was performed in 64.6% of the infants. The iKMC group showed a non-significant trend toward higher SpO₂ levels. Mean SpO₂ was 76.06% in the iKMC group versus 70.98% in the non-iKMC group; at 420 s, it was 95.13% versus 93.77%. HR was significantly higher in the iKMC group at all time points, averaging 102.2 bpm at 120 s compared to 87.1 bpm in the non-iKMC group. Combining iKMC with DCC improves hemodynamic stability and oxygenation in MLPT infants, with higher HR and earlier stabilization of SpO₂ levels.