Hyponatremia in the neonatal intensive care unit: incidence, risk factors and effect on mortality
BMC Pediatrics, vol.26, no.1, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 26 Issue: 1
- Publication Date: 2026
- Doi Number: 10.1186/s12887-026-06582-3
- Journal Name: BMC Pediatrics
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, CINAHL, EMBASE, MEDLINE, Directory of Open Access Journals, Biomedical Reference Collection: Corporate Edition (EBSCO), Health Research Premium Collection (ProQuest)
- Keywords: Hyponatremia, Incidence, Mortality, Neonatal intensive care unit (NICU), Newborn, Preterm, Risk factors
- Ondokuz Mayıs University Affiliated: Yes
Abstract
Objective: The aim of this study was to evaluate the incidence of hyponatremia, risk factors, and its effect on mortality in neonates hospitalized in the neonatal intensive care unit (NICU). Methods: This retrospective study was conducted in the NICU of a university hospital in Türkiye over a seven-month period in 2016. All 527 infants admitted to the NICU during the study period were included in the study. Hyponatremia was defined as a serum sodium level < 135 mEq/L. Demographic data, clinical diagnoses, fluid therapy, diuretic use, and survival outcomes were analyzed. Multivariate logistic regression analysis was used to identify independent risk factors. Results: The incidence of hyponatremia in the cohort was 21.2% (112/527). The incidence was higher in preterm (23.6%) and extremely low birth weight (ELBW) infants (61.1%). Hyponatremia was mild in the majority of cases (79.9%). The average gestational age and birth weight of hyponatremic infants were significantly lower than those of non-hyponatremic ones (p = 0.011 and p = 0.038, respectively). In logistic regression analysis, low gestational age was identified as an independent risk factor for hyponatremia (OR = 0.905, p = 0.031). Respiratory system disorders (55.4%) were the most common accompanying comorbidity. Diuretic use in 31.8% and administration of hypotonic fluids (1/5 normal saline) in 45.2% of babies were common associated factors. Mortality was significantly higher in hyponatremic babies when compared with non-hyponatremic ones (10.7% vs. 2.9%; p = 0.001). Conclusion: Hyponatremia is a common and serious condition in the NICU, associated with a significant increase in mortality; with low gestational age being a key independent risk factor. The frequent use of diuretics and hypotonic fluids highlights potential iatrogenic contributions. These findings suggest the need for careful serum sodium monitoring and a re-evaluation of fluid management protocols, especially for vulnerable ELBW preterm infants.