Brain natriuretic peptide (BNP) is an important tool for diagnosis, risk stratification and prognosis in pediatric patients with heart failure1. In newborn, after delivery, the BNP plays an important role in cardiopulmonary hemodynamics by stimulating vasodilatation and diuresis. The gradual decrease in pulmonary pressure and the initiation of diuresis as expression of renal maturity could explain the subsequent decrease in serum values. This would suggest that, in healthy newborns, BNP values should be found within a given ranges. However, the evidence suggests an important variability in BNP values 2 - 4. In the other hand, in the newborn with respiratory distress BNP could have a high negative predictive value to rule out acute myocardial processes, as responsible for clinical deterioration, from infectious, metabolic or respiratory processes; with a potential of improvement in medical care. Even the increased use of this biomarker in clinical practice, until our knowledge, BNP normal values remain unknown in the healthy newborn. Therefore, the investigators performed a pioneer study to establish normal values in healthy newborn population. Multi-center, prospective and observational study was carried out. Objective: To establish normal BNP values in healthy newborn.

Inclusion Criteria:

• healthy mother with pregnancy at term (38 to 42 gestational weeks) with adequate prenatal care.
• newborns with Apgar score ≥ 7 at 0 and 5 minutes respectively.

Exclusion Criteria:

• newborns of mothers with pregnancy-associated diseases.
• newborns with chromosomopathies detected during the antenatal care and newborns with signs of cardiac and/or respiratory compromise.

Healthy term newborn obtained by vaginal delivery and/or cesarean section.