B-type natriuretic peptide levels normalise in preterm infants without a patent ductus arteriosus by the fifth postnatal day

Aim: Few published reports have established B-type natriuretic peptide (BNP) levels in preterm infants without a patent ductus arteriosus (PDA). This study addressed that gap in our knowledge by establishing a reference range for BNP levels during the first two weeks of life in preterm infants without a PDA.

Methods: We enrolled 36 preterm infants between 24 and 32 weeks of gestation in this prospective, noninterventional study. Infants with a PDA, congenital heart disease, possible or confirmed sepsis and, or, meningitis, or perinatal depression requiring chest compressions were excluded. BNP levels were measured on postnatal days one, five, 10 and 15, with an echocardiogram on day five. Statistical analyses were performed using the ANOVA and Mann-Whitney U-tests.

Results: BNP levels were significantly higher on day one than on days five, 10 and 15, and there was no statistical difference between days five, 10 and 15. The levels were not statistically different between infants of less than and greater than 29 weeks of gestation.

Conclusion: BNP levels were significantly elevated on postnatal day one in preterm infants without a PDA, but then decreased by day five and continued to stay low after that. Gestational age did not have an effect on BNP levels.