Reference values for cord blood N-terminal pro-B-type natriuretic peptide in preterm neonates

Purpose The aim of this work is to establish reference values for cord blood N-terminal pro-brain natriuretic peptide (NT-proBNP) in preterm neonates and to examine the associations between NT-proBNP concentrations and perinatal factors. Methods Cord blood NT-proBNP levels were measured in 174 preterm infants born at 26–36 weeks of gestation. Infants were stratified by gestational age (GA), and reference intervals for cord blood NT-proBNP were calculated as the 5th–95th percentiles for each GA subgroup. Correlations between NT-proBNP concentrations and selected perinatal variables were also assessed. Results The study revealed that NT-proBNP levels showed negative correlations with GA, birth weight (BW), and Apgar scores at 1 and 5 min, with correlation coefficients of −0.229, −0.278, −0.264, and −0.290, respectively, all statistically significant at P < 0.01. However, no significant associations were observed between NT-proBNP concentrations and infant gender, cord blood pH, premature rupture of membranes (PROM), mode of delivery, or early ejection fraction (EF). Conclusion Reference intervals for cord blood NT-proBNP in preterm infants should be stratified by GA, with levels decreasing as GA and BW increase. Neither vaginal delivery nor PROM was associated with elevated NT-proBNP levels, suggesting that these perinatal factors do not independently induce significant cardiovascular stress in the fetus.