Breast-feeding-associated hypernatremia: retrospective analysis of 169 term newborns.

BACKGROUND: The aim of the present paper was to define the incidence, complications, morbidity and mortality of hypernatremic dehydration due to inadequate breast-feeding in a neonatal intensive care unit.

METHODS: A retrospective study was carried out between 2002 and 2005, to identify the term breast-fed neonates with serum sodium level > or =150 mEq/L at the Ministry of Health Ankara Diskapi Children's and Research Hospital.

RESULTS: The incidence of hypernatremic dehydration secondary to inadequate breast-feeding was 4.1%, occurring in 169 term infants among 4136 hospitalized term neonates with the following characteristics: mean gestational age, 39.1 weeks (37-42 weeks); birthweight, 3352 g (2200-4500 g); mother's age, 26.1 years (17-38 years); weight loss, 15.9% (5.4-32.7%); proportion of spontaneous vaginal deliveries, 75.7%; and proportion of first-time mothers, 74.6%. Major presenting symptoms were neonatal jaundice (47.3%) and poor infant suck (29.6%). The median sodium; blood urea nitrogen (BUN); and creatinine levels on admission were 155 mmol/L (150-194 mmol/L), 35 mg/dL (7-253 mg/dL), and 0.9 mg/dL (0.2-10 mg/dL), respectively. Major complications were as follows: acute renal failure, 82.8%; elevated liver enzymes, 20.7%; disseminated intravascular coagulation, 6.5%; brain edema, 5.2%; intracranial hemorrhage, 3.6%; cavernous sinus thrombosis, 1.2%; and bilateral iliac artery thrombosis, 0.6%. Ten patients (5.9%) developed seizure within the first 24 h of rehydration therapy with a mean sodium decrease of 11.9 mmol/L per day (4-19 mmol/L per day). Two patients (1.2%) died. There were positive correlation between weight loss and serum sodium, BUN, bilirubin levels (P < 0.01); there was no correlation between weight loss and mothers' age, education level, delivery route, or first-born status (P > 0.05).

CONCLUSIONS: Hypernatremic dehydration in neonates due to inadequate breast-feeding is a serious, potentially devastating and life-threatening disorder, and can damage the central nervous system. Follow up of infants for adequate breast-feeding is important. Pediatricians must maintain a high level of suspicion, especially in cases of pathologic infant weight loss after delivery.