Weight loss and hypernatremia in breast-fed babies: frequency in neonates with non-hemolytic jaundice.

Objective: The aim of this study was to determine what proportion of newborns admitted with idiopathic non-hemolytic hyperbilirubinemia exhibit severe weight loss and hypernatremia.

Methods: The prospective study involved 115 infants >48 h old who were admitted with jaundice between July 2002 and July 2003, and had unconjugated bilirubin levels >12 mg/dL. Premature babies (gestational age <37 weeks) and those with hemolytic jaundice and other pathologic causes of non-hemolytic jaundice were excluded. Postnatal age (days) at admission, bodyweight at admission, weight change since birth (percentage weight loss calculated at admission) and mode of feeding (breast-feeding, formula feeding, mixed feeding) were recorded. Severe weight loss was defined in babies who showed >10% weight loss or had not regained enough to reach birthweight by postnatal day 10. Serum Na levels and breast-milk Na levels were also measured.

Results: Twenty-eight (33%) of the 86 newborns with idiopathic hyperbilirubinemia in the study exhibited severe weight loss. Almost all the 86 babies were exclusively breast-fed, and 10 babies (12%) had severe weight loss combined with hypernatremia. The group with severe weight loss and hypernatremia had higher breast-milk Na levels than the other infants.

Conclusion: The results indicate that a large proportion of babies with non-hemolytic jaundice have severe weight loss, and that breast-fed newborns with the combination of weight loss and hypernatremia may present with non-hemolytic jaundice.