Aims: To study incidence and risk factors of early neonatal dehydration in a Norwegian population based cohort.
Methods: Term neonates admitted to a paediatric department during 2002-2008 with a weight loss > or = 12% within three weeks of age were identified retrospectively through review of medical records. For each patient a sex-matched control group of two full-term infants was selected to assess risk factors for dehydration.
Results: A total of 38 of 37 321 infants (1.0 per thousand) were admitted at a median age of 6 (interquartile range 5-12) days, and the admission rate increased during the study period (p for trend = 0.008). Simultaneously, mean nursery stay decreased from 3.5 to 2.7 days (p = 0.022). Mean weight loss was 15.0% of birth weight and 17 of 29 (58.6%) had serum sodium above 145 mmol/L. The only significant difference between patients and controls was that mothers of patients were older (32.3 +/- 5.0 vs. 29.4 +/- 5.4 years, p = 0.005).
Conclusion: Short nursery stay may be a risk factor for dehydration in newborn infants.