title: Effects of maternal prone position on the umbilical arterial flow.
abstract: OBJECTIVE
  The objective of our study was to clarify the effect of the maternal prone position on the feto-placental flow. In this position, the uterine compression of the large maternal vessels was expected to be completely eliminated.
  
  
  METHODS
  Twenty-three normal pregnant women were cross-sectionally examined in the supine, the left lateral, the right lateral and the prone position. The systolic/diastolic ratios for the umbilical artery were calculated for each position.
  
  
  RESULTS
  The umbilical arterial systolic/diastolic ratio in the prone position significantly decreased compared with that in the supine position. The left and right lateral position showed no significant change in the systolic/diastolic ratio.
  
  
  CONCLUSIONS
  The maternal prone position can provide complete relief of uterine compression of the large maternal vessels.
authors.affiliation: Department of Obstetrics and Gynaecology, School of Medicine, Osaka City University, Osaka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Nakai
authors.forename: M
authors.initials: M
authors.lastname: Mine
authors.forename: J
authors.initials: J
authors.lastname: Nishio
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: M
authors.initials: M
authors.lastname: Imanaka
authors.forename: S
authors.initials: S
authors.lastname: Ogita
mesh_terms: D003430:Cross-Sectional Studies; D003971:Diastole; D005260:Female; D006801:Humans; D011247:Pregnancy; D016684:Prone Position; D012039:Regional Blood Flow; D013599:Systole; D014469:Umbilical Arteries / Q000502:physiology*