title: Maternal oxygen transport variables during the third trimester of normal pregnancy.
abstract: OBJECTIVE
  The aim of this study was to measure and calculate oxygen transport variables in uncomplicated term pregnancies.
  
  
  METHODS
  Ten normotensive primiparous women between 36 and 38 weeks' gestation underwent pulmonary and radial arterial catheterization as part of a larger study. Seven women had studies repeated at approximately 12 weeks post partum. Measurements were made with patients in the left lateral recumbent position after a 30-minute stabilization period. Cardiac output was measured with the thermodilution technique. Blood samples were obtained simultaneously from the pulmonary and radial arteries and analyzed in duplicate for oxygen content with a blood gas analyzer.
  
  
  RESULTS
  The oxygen contents of both arterial and mixed venous blood are significantly lower (P <.05) in the third trimester of pregnancy (15.96 and 11.97 mL/dL, respectively) than in the postpartum period (18.00 and 13.54 mL/dL). The fall in oxygen content during pregnancy prevents any significant increase in oxygen delivery in the third trimester (867. 59 mL/min) relative to the postpartum period (806.50 mL/min, P not significant).
  
  
  CONCLUSIONS
  This is the first report of directly measured oxygen transport variables in healthy pregnant women.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas, USA.
authors.forename: G D
authors.initials: GD
authors.lastname: Hankins
authors.forename: S L
authors.initials: SL
authors.lastname: Clark
authors.forename: E
authors.initials: E
authors.lastname: Uckan
authors.forename: J W
authors.initials: JW
authors.lastname: Van Hook
mesh_terms: D001692:Biological Transport; D002302:Cardiac Output; D005260:Female; D005865:Gestational Age; D006801:Humans; D007700:Kinetics; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D011651:Pulmonary Artery; D017534:Radial Artery