Previous studies assessing BNP in preterm infants showed moderate associations with pulmonary hypertension27,28 and BPD development.11,12,29,30 A recent systematic review of observational studies assessed NT-proBNP as an early marker for respiratory morbidity in preterm infants.29 Only two small studies with considerable risk of bias were included, thus quality of evidence was deemed to be low. Here, NPPB is linked to bronchopulmonary dysplasia.