Abstract
Sodium plays a role in DNA synthesis, cell proliferation, and absorption of nutrients, and may have an underappreciated role in the growth of infants. Serum sodium is the most common measure of sodium status, but urinary sodium better reflects total body sodium status because it accounts for renal conservation of sodium, an extracellular electrolyte. This article discusses the relationship between inadequate sodium status and growth in premature infants. Implications of prematurity on the gastrointestinal (GI) tract and kidney function and GI losses, because of GI disease on sodium status and growth, and the effects of sodium supplementation are also described.