A study of serum sodium and potassium levels in normal term neonates

Abstract

Introduction: Transition from foetal to neonatal life is associated with major changes in fluid and electrolyte levels due to homeostatic control. Aims & objective: This study was planned to study changes of serum sodium and serum potassium in cord blood and during first week of life. Material & method: 100 Normal term neonates with gestational age>37weeks & birth weight >2100gm were included in the study. Serum sodium and potassium were studied in cord blood, 24hrs, 48hrs, 7 th day of life and mean, range & standard deviation were calculated. Results: The range of serum sodium in cord blood, at 24 hrs, 48 hrs & 7 days in our study was 128.0156.0 meq/L, 128.0150.0 meq/L,134.0154.0 meq/L & 128.0 150.0 meq/L respectively. The range of serum potassium in cord blood, at 24 hrs, 48 hrs & 7 days in our study was 4.2 7.2 meq/L, 4.0 6.6 meq/L, 4.0 6.5 meq/L & 3.8 6.2 meq/L respectively. Summary: This study showed very wide range of serum sodium and potassium levels that seem to be abnormally high or low in healthy term neonate in cord blood and during first week of life but these are actually normal for that neonatal period depending upon gestational and post natal age. Conclusion: The normal values of Serum sodium and serum potassium in neonates are different from other age groups and it varies with postnatal age and gestational age so same reference range of electrolytes should not be used in all neonates instead a reference range derived from large neonatal datasets of varied gestational and postnatal age should be used, such as those presented here for healthy term neonates.