Hypernatraemic dehydration in newborns

Background: In several industrialised countries hypernatraemic dehydration is increasingly reported in healthy newborns during the first few days of life, probably associated with exclusive breastfeeding. This condition may result in convulsions, permanent brain damage and death. Excessive weight loss is an early indicator, other symptoms are not specific. Objective: Detection and management of hypernatraemic dehydration in newborns with weight loss above 10%. Methods: Prospective cohort study from July 2003 to January 2004 in the maternity of the University Hospital Zurich. All term newborns with birth weight above 2500g were weighed daily until discharge. When weight dropped more than 10% below birth weight, serum sodium was measured from a heel prick. Infants with moderate hypenatraemia (serum sodium=146–149 mmol/l) were fed supplementary milk. Infants with severe hypernatraemia (serum sodium above 149 mmol/l) got intravenous fluid. Results: 1010 healthy term newborns were recruited, 939 (93%) were breast fed, 34 newborns had weight loss above 10% (all breast fed), 19 infants had hypernatraemia, 6 of them had severe hypernatraemia. All infants regained weight within 24 hours after treatment. The severity of hypernatraemia did not correlate with the amount of weight loss. Conclusion: The incidence of hypernatraemic dehydration in our clinic is 3.4%, which is higher than previously reported. With daily weight control and supplemental fluid with weight loss >10% rapid recovery is possible. Therefore daily monitoring of weight in exclusively breastfed infants allows early intervention and prevention of severe sequelae.