Background: Elevated cord blood levels of interleukin-6 and N-terminal pro-brain natriuretic peptide were associated with neonatal complications; however, simultaneously obtained values have not been compared to date.
Objectives: To study the association of cord blood levels of IL-6 and NT-proBNP with perinatal variables of premature infants and examine the relationship between the obtained values.
Methods: Cord blood IL-6 (89 samples) and NT-proBNP (66 samples) levels obtained from infants delivered before 32 weeks of gestation were analyzed for associations with perinatal variables and possible correlation between both samples.
Results: Lower gestational age, no antenatal exogenous steroids, low Apgar scores at 1 minute and delivery at a high birth order, were all associated with more infants having elevated IL-6 levels (P = 0.02, P = 0.03, P = 0.03 and P = 0.001, respectively). None of the infants with necrotizing enterocolitis (n=6) had high IL-6 levels (P = 0.01). Increased NT-proBNP levels were associated with low Apgar scores at 1 minute (P = 0.01) and the presence of clinical chorioamnionitis (P = 0.06). Controlling for gestational age, a weak positive correlation was demonstrated between IL-6 and NT-proBNP levels in infants of 24-27 weeks gestational age (R2 = 0.151, P = 0.08), but not among the more mature infants.
Conclusions: Although both IL-6 and NT-proBNP values were significantly associated with low I minute Apgar scores, our results do not support utilization of these cord blood levels as the sole tool to predict neonatal outcome.