Breastfeeding-Associated Hypernatremia: Are We Missing the Diagnosis?

To assess the incidence and complications of breastfeeding-associated hypernatremic dehydration among hospitalized neonates. A retrospective study was conducted at Children's Hospital of Pittsburgh over a 5-year period, to identify otherwise healthy term and near-term (> or =35 weeks of gestation) breastfed neonates ( or =150 mEq/L and no explanation for hypernatremia other than inadequate milk intake. The incidence of breastfeeding-associated hypernatremic dehydration among 3718 consecutive term and near-term hospitalized neonates was 1.9%, occurring for 70 infants. These infants were born primarily to primiparous women (87%) who were discharged within 48 hours after birth (90%). The most common presenting symptom was jaundice (81%). Sixty-three percent of infants underwent sepsis evaluations with lumbar puncture. No infants had bacteremia or meningitis. Infants had hypernatremia of moderate severity (median: 153 mEq/L; range: 150-177 mEq/L), with a mean weight loss of 13.7%. Nonmetabolic complications occurred for 17% of infants, with the most common being apnea and/or bradycardia. There were no deaths. Hypernatremic dehydration requiring hospitalization is common among breastfed neonates. Increased efforts are required to establish successful breastfeeding.