Reference ranges for preductal oxygen saturation and heart rate in moderate and late preterm infants with deferred cord clamping.

Introduction: Moderate and late preterm (MLPT) infants represent a substantial percentage of all preterm infants and frequently need support in the delivery room (DR). Deferring cord clamping (DCC) improves SpO2 and heart rate (HR) stabilization in term infants. However, data on MLPT infants are limited.

Methods: Prospective observational study collecting SpO2 and HR by pulse-oximetry (PO) in healthy MLPT infants with DDC to construct percentile graphs for the first 10 minutes after birth.

Results: 96 MLPT infants were monitored for preductal SpO2 and HR, and percentiles were calculated. SpO2 mean was significantly lower for MLPT than for term infants during the first six minutes after birth, and 15% didn't achieve SpO2 > 85% in the first five minutes after birth. HR was significantly lower in MLPT infants in the first 4 minutes after birth; however, HR consistently remained above bradycardic values (> 100 bpm). NICU admission and postnatal complications were not different between MLPT achieving SpO2 > 85% or not.

Conclusions: MLPT infants with DCC achieved stable SpO2 and HR significantly later, 6 min and 4 min, respectively than term infants. In addition, 15% of MLPT infants didn't achieve SpO2  85% at five minutes after birth. However, admission to the NICU and clinical evolution didn't differ from newborns with SpO2 85% at 5 minutes. Larger studies including long-term follow-up are needed to assess if lower SpO2 in the first five minutes has clinical consequences in non-resuscitated MLPT.