Background & objectives: Weight loss and hypernatremic dehydration is a common problem in infants with inadequate nutrition. Determination of risk factors and clinical characteristics of these neonates may help to prevent or early detection of hypernatremia. This study designed to determine the prevalence of clinical signs and risk factors for hypernatremic dehydration.

Methods: This study is a sectional descriptive study that conducted on 418 newborns during 1385 to 1393 AHS that referred to Ghaem hospital in Mashhad. The hypernatremic group consisted of 197 neonates with serum sodium level higher than 150 mg/dl and 221 isonatremic newborns with sodium level less than 150 mmol/L were included as controls. Both groups were compared in terms of clinical symptoms of dehydration and maternal risk factors. All data were recorded and coded. Data analysis performed using paired T test and chi square tests by SPSS 16 software.

Results: In the present study, 2.8% of infants were hypernatremic. The most common symptoms were neonatal jaundice (62.2%), hyperthermia (25.8%), lethargy (23.6%), agitation (20.8 %) and mucous membranes dryness (17.2%). Problems in pregnancy (p=0.002), inappropriate feeding techniques (p=0.000), the first lactation duration (p=0.022) and frequency per day (p=0.000) had statistically significant difference between case and control groups.

Conclusion: Prevalence of hypernatremic dehydrationis considerable in our study and identifying the risk factors may help to reduce its incidence or exacerbation. Weight loss, especially in newborns having jaundice, hyperthermia and irritability, may be helpful in the early diagnosis of hypernatremic dehydration