Neonatal weight loss exceeding 10% of birth weight

Specialty: Pediatrics.

• Pathological neonatal weight loss
• early neonatal dehydration due to breastfeeding problems

Why it occurs

• Ineffective breastfeeding or latch and latch problems (insufficient transfer of colostrum or breast milk in the first days due to inadequate technique, short lingual frenulum or weak suction)
• Delay or failure in lactogenesis II or maternal "milk let-down" (related to scheduled cesarean sections, retained placental membranes, severe postpartum hemorrhage, uncontrolled pain or maternal diabetes)
• Neonatal hypernatremic dehydration (excessive loss of free water in relation to sodium due to low fluid intake, which can cause an increase in the concentration of sodium in the blood with serious neurological repercussions)
• Underlying organic neonatal pathology that weakens the infant (occult neonatal sepsis, ductus-dependent congenital heart disease, hypoxic-ischemic encephalopathy or inborn errors of metabolism that prevent adequate feeding).

Initial workup

Detailed evaluation of a breastfeeding session by expert personnel using observational breastfeeding scales (such as the LATCH scale). Rigorous recording of daily neonatal weight always using the same scale and undressing conditions. Urgent blood analysis in case of weight loss > 12% or clinical suspicion of hypernatremic dehydration: Serum sodium (to rule out hypernatremia, defined by Na > 145-150 mEq/L, which increases the risk of intracranial hemorrhage and cerebral edema due to neuronal cell dehydration), chloride, potassium, urea, plasma creatinine and capillary blood glucose. Total and fractionated bilirubin (to assess jaundice due to dehydration/breastfeeding).

Standard management

• The mainstay of treatment is not pharmacological, but immediate supplementation with expressed breast milk, donated human milk or starter milk formula (using techniques that protect lactation, such as the finger-tube or sippy cup method). If the neonate presents severe hypernatremic dehydration (serum sodium > 150 mEq/L) and neurological compromise, intravenous hydration is indicated: 0.9% Physiological Saline in boluses of 10 to 20 ml/kg if hypovolemic shock is present; followed by maintenance infusion calculating the fluid deficit very conservatively to decrease serum sodium slowly (no more than 0.5 mEq/L per hour or 10 mEq/L in 24 hours) to avoid the appearance of acute cerebral edema, seizures or death.