Maternal oxygen transport variables during the third trimester of normal pregnancy

Am J Obstet Gynecol. 1999 Feb;180(2 Pt 1):406-9. doi: 10.1016/s0002-9378(99)70223-1.

Abstract

Objective: The aim of this study was to measure and calculate oxygen transport variables in uncomplicated term pregnancies.

Study design: 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).

Conclusion: This is the first report of directly measured oxygen transport variables in healthy pregnant women.

MeSH terms

  • Biological Transport
  • Cardiac Output
  • Female
  • Gestational Age*
  • Humans
  • Kinetics
  • Oxygen / blood*
  • Oxygen Consumption
  • Pregnancy
  • Pregnancy Trimester, Third
  • Pulmonary Artery
  • Radial Artery

Substances

  • Oxygen