title: The contribution of hemolysis to early jaundice in normal newborns.
abstract: OBJECTIVE
  Neonatal jaundice is the result of an imbalance between bilirubin production and elimination, and our objective was to clarify the contribution of an increase in bilirubin production to hyperbilirubinemia in newborns.
  
  
  METHODS
  We measured the end-tidal carbon monoxide concentration corrected for ambient carbon monoxide concentration in 108 jaundiced newborns (total serum bilirubin level >75th percentile) and 164 control newborns in our well-infant nursery, for the first 4 days after birth.
  
  
  RESULTS
  Mean end-tidal carbon monoxide levels decreased in the control infants in the first 4 days but increased in the hyperbilirubinemic group. The differences between the jaundiced and nonjaundiced infants were statistically significant on all days.
  
  
  CONCLUSIONS
  Before hospital discharge, most infants with bilirubin levels >75th percentile are producing significantly more bilirubin than those with lower bilirubin levels. Because the ability of newborns to conjugate bilirubin is significantly impaired in the first few days, even a small increase in the rate of production can contribute to the development of hyperbilirubinemia. These data suggest that increased heme catabolism is an important mechanism responsible for hyperbilirubinemia in the first 4 days after birth.
authors.affiliation: Department of Pediatrics, William Beaumont Hospital, 3601 W 13 Mile Rd, Royal Oak, Michigan 48073, USA. jmaisels@beaumont.edu
authors.forename: M Jeffrey
authors.initials: MJ
authors.lastname: Maisels
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kring
mesh_terms: D001663:Bilirubin / Q000378:metabolism; D001724:Birth Weight; D002248:Carbon Monoxide / Q000032:analysis*; D005260:Female; D005865:Gestational Age; D006418:Heme / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D007231:Infant, Newborn; D007567:Jaundice, Neonatal / Q000378:metabolism / Q000503:physiopathology*; D008297:Male
chemical_list: D006418:Heme; D002248:Carbon Monoxide; D001663:Bilirubin