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 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.