title: A longitudinal study of cardiac output in normal human pregnancy.
abstract: OBJECTIVE
  Our purpose was to investigate the maternal hemodynamic and cardiac structural changes that occur during pregnancy.
  
  
  METHODS
  Eighteen women underwent serial echocardiography beginning at 8 to 11 weeks' gestation, then at monthly intervals throughout pregnancy and at 6 and 12 weeks post partum. Cardiac output was measured by pulsed- and continuous-wave Doppler at the aortic valve. Left ventricular chamber size, wall thickness, and mass were determined by M-mode echocardiography. Ventricular diastolic function was assessed by Doppler recording of mitral inflow.
  
  
  RESULTS
  Cardiac output by pulsed Doppler increased from 6.7 +/- 0.6 L/min at 8 to 11 weeks' gestation to 8.7 +/- 1.4 L/min at 36 to 39 weeks' gestation before falling to 5.7 +/- 0.7 L/min 12 weeks post partum. Heart rate increased 29%, and stroke volume increased 18%. Left ventricular mass increased because of an increase in wall thickness. Peak mitral A wave velocity increased in late pregnancy. Cardiac output by pulsed and continuous-wave Doppler was similar.
  
  
  CONCLUSIONS
  Cardiac output continues to increase even in late pregnancy. Left ventricular mass increases because of increased wall thickness. The mitral flow velocity findings suggested decreased ventricular compliance or increased preload.
authors.affiliation: Department of Obstetrics and Gynecology, University of Tennessee, Memphis 38103.
authors.forename: W C
authors.initials: WC
authors.lastname: Mabie
authors.forename: T G
authors.initials: TG
authors.lastname: DiSessa
authors.forename: L G
authors.initials: LG
authors.lastname: Crocker
authors.forename: B M
authors.initials: BM
authors.lastname: Sibai
authors.forename: K L
authors.initials: KL
authors.lastname: Arheart
mesh_terms: D000328:Adult; D001021:Aortic Valve / Q000000981:diagnostic imaging; D002302:Cardiac Output; D004452:Echocardiography; D015150:Echocardiography, Doppler / Q000379:methods; D005260:Female; D006439:Hemodynamics; D006801:Humans; D008137:Longitudinal Studies; D009200:Myocardial Contraction; D011247:Pregnancy / Q000502:physiology*; D016277:Ventricular Function, Left