title: Natremia of healthy term newborns at 48 h of life: influence of feeding patterns.
abstract: OBJECTIVE
  To describe natremia in healthy term newborns and determine whether there is a relationship between blood sodium and feeding patterns.
  
  
  METHODS
  All normal newborns, admitted to the nursery between January and March 2004 were eligible for this prospective cohort study. Inclusion criteria were: > or =37 weeks of gestational age, birth weight > or =2500 g, Apgar scores > or =7 at 5 and 10 min and normal physical examination. A capillary blood sample was taken at 48+/-12 h of life.
  
  
  RESULTS
  Blood samples from 126 newborns were analyzed. Mean gestational age was 39.6 weeks, birth weight was 3414 g and weight loss at 48 h of life was 6.5% of birth weight. Mean capillary blood sodium was 141 mmol/L (SD 3.4). Exclusively, breast-fed newborns had statistically higher mean blood sodium (141 mmol/L, SD 3.0) than the non-exclusively breast-fed+formula fed group (139 mmol /L, SD 3.7). There was a significant linear association between blood sodium and the quantity of milk supplements received as well as between blood sodium and weight loss.
  
  
  CONCLUSIONS
  Most newborns have blood sodium values within a narrower range than previously described in the literature. We also demonstrate that the exclusively breast-fed infants appear to have marginally but statistically higher values of blood sodium than non-exclusively breast-fed and formula-fed infants.
authors.affiliation: Department of Paediatrics, CHU Sainte-Justine, University of Montreal, Montreal, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Anctil
authors.forename: A
authors.initials: A
authors.lastname: Carceller
authors.forename: I
authors.initials: I
authors.lastname: Chevalier
authors.forename: M
authors.initials: M
authors.lastname: Gonthier
authors.forename: A C
authors.initials: AC
authors.lastname: Bernard-Bonnin
authors.forename: J
authors.initials: J
authors.lastname: Cousineau
authors.forename: E
authors.initials: E
authors.lastname: Delvin
mesh_terms: D005247:Feeding Behavior; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D012964:Sodium / Q000097:blood*
chemical_list: D012964:Sodium