Incidence of dehydration and hypernatremia in exclusively breast-fed infants.

Objectives: To verify in exclusively breast-fed, term infants the incidence of hypernatremic dehydration and identify possible maternal and/or infant fac- tors that interfere with successful breast-feeding. Study Design: We prospectively included all healthy breast-fed neonates re- ferred to our Neonatology Unit between October 1999 and March 2000. All neonates with a weight loss ≥10% of birth weight had a breast-feeding test and a determination of serum sodium, urea, and base excess. Student ttest and chi-square test were used for statistical analysis of the data. Results: Of 686 neonates, 53 (7.7%) had a weight loss ≥10% of the birth weight, and 19 also had hypernatremia. These 53 neonates had a significantly higher incidence of caesarean delivery and lower maternal education than neonates with a weight loss <10%. Conclusion: Our prospective study demonstrates that a weight loss ≥10% during the first days of life is frequent. Daily weight evaluation, careful breast-feeding assessment, and early routine postpartum follow-up are effec- tive methods to prevent hypernatremic dehydration and promote breast-feed- ing. (J Pediatr 2001;139:673–5)