High sodium in breast milk can precipitate Neonatal Hypernatremia: A case report

A primigravida mother delivered a healthy girl at term via spontaneous vaginal delivery, with the baby weighing 4,080 g at birth. At the 2-week well-child check, the baby had lost about 30% of her birth weight, weighing 2800 g. She was exclusively breastfed every 2 hours for 10 minutes on each breast and had 6 wet diapers per day. 

At presentation,the baby was active with no lethargy. The pregnancy and ultrasounds were normal, with no oligohydramnios or polyhydramnios.On examination, the baby was alert but had dry mucous membranes, cracked lips, and a capillary refill time >3 seconds. Her skin was soft and doughy.

Laboratory results showed: sodium 196 mEq/L, potassium 6.7 mEq/L, chloride 155 mEq/L, bicarbonate 15 mEq/L, urea 440 mg/dL, creatinine 4.08 mg/dL, phosphorus 7.8 mg/dL, and uric acid 19.9 mg/dL. The urine dipstick showed a specific gravity of 1.019, 2+ protein, and 2+ glucose. Urinary sodium was 152 mEq/L, potassium 25.4 mEq/L, creatinine 34.1 mg/dL, osmolarity 736 mosmol/kg, and serum osmolarity 475 mosmol/kg. Liver enzymes, coagulation studies, renaland bladder ultrasounds, and ECG were normal.

The baby was admitted for parenteral rehydration and hypernatremia correction. The sodium in breast milk was 90 mEq/L. Breastfeeding was stopped, and hypernatremia was corrected with IV hydration until sodium levels, electrolytes, and renal function normalized. The baby gained weight well before discharge. 

Neonatal hypernatremia is a serious condition in exclusively breastfed infants due to inadequate milk secretion and feeding issues. Early monitoring of mother and baby for proper feeding is crucial. High sodium in breast milk should be suspected in healthy infants with weight loss and hypernatremia. Further studies are needed to assess breastfeeding management and the causes of high sodium in breast milk.

Source: El Masri M, Samotiy-Hanna L, Ghabril R, et al. Case Rep Pediatr. 2024;2024:8838362. Published 2024 Mar 8. doi:10.1155/2024/8838362