title: Effect of change in posture on maternal functional hemodynamics at 35-37 weeks' gestation.
abstract: OBJECTIVE
  To evaluate the effect of posture change from the supine to the sitting position and before and after passive leg raising on maternal functional hemodynamics in pregnant women at 35-37 weeks' gestation, and to compare the changes in pregnancies that subsequently developed pre-eclampsia (PE) or gestational hypertension (GH) with those that remained normotensive.
  
  
  METHODS
  In 2764 singleton pregnancies at 35-37 weeks' gestation, maternal cardiovascular parameters were measured using an automated non-invasive cardiac monitor. The hemodynamic response to a change from the supine to the sitting position and before and after passive leg raising in the left lateral position was examined and compared between women who subsequently developed PE or GH and those who remained normotensive.
  
  
  RESULTS
  In normotensive singleton pregnancies at 35-37 weeks' gestation, both change from the supine to the sitting position and passive leg raising were associated with an increase in cardiac index and stroke volume index and a decrease in total peripheral resistance index; there was a small increase in mean arterial pressure with both postural changes and a slight decrease in heart rate with passive leg raising. In pregnancies that subsequently developed PE or GH, compared with normotensive pregnancies, cardiac index and stroke volume index were lower and total peripheral resistance index was higher. In general, change from the supine to the sitting position and passive leg raising were associated with similar but less marked changes in cardiovascular parameters as in normotensive pregnancies.
  
  
  CONCLUSIONS
  Paradoxically, in late third-trimester normal pregnancy, both change from the supine to a sitting position and passive leg raising may result in an increase in preload with a consequent increase in cardiac and stroke volume indices and a decrease in total peripheral resistance index. In pregnancies that develop PE or GH, the effects of postural change on cardiovascular parameters are similar but less marked than in normotensive pregnancies. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College London, London, UK.
authors.forename: G P
authors.initials: GP
authors.lastname: Guy
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College London, London, UK.
authors.forename: H Z
authors.initials: HZ
authors.lastname: Ling
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College London, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Machuca
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College London, London, UK.|Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, Hong Kong.
authors.forename: L C
authors.initials: LC
authors.lastname: Poon
authors.affiliation: Harris Birthright Research Centre for Fetal Medicine, King's College London, London, UK.
authors.forename: K H
authors.initials: KH
authors.lastname: Nicolaides
mesh_terms: D000328:Adult; D062186:Arterial Pressure / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002307:Cardiography, Impedance; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011187:Posture / Q000502:physiology*; D011225:Pre-Eclampsia / Q000503:physiopathology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D037841:Pregnant People; D011446:Prospective Studies; D012815:Signal Processing, Computer-Assisted; D013318:Stroke Volume / Q000502:physiology*
keywords: cardiac output; maternal cardiovascular function; posture; pre-eclampsia; third-trimester screening; total peripheral resistance