title: Dye-dilution techniques using aminohippurate sodium: do they accurately reflect amniotic fluid volume?
abstract: OBJECTIVE
  To determine whether the dye-dilution technique using aminohippurate sodium accurately measures amniotic fluid volume.
  
  
  METHODS
  Singleton pregnancies with intact membranes undergoing a Cesarean delivery had their amniotic fluid volume assessed by the dye-dilution technique and direct measurement.
  
  
  RESULTS
  Fifteen women were prospectively assessed. Six patients had their amniocentesis on the delivery table and nine patients at 4-24 h prior to the Cesarean delivery. The six women undergoing an amniocentesis just before delivery had good concordance between the dye-determined and direct measurement of amniotic fluid volume (r = 0.99, p = < 0.001). Among the nine women with varying times from amniocentesis to direct measurement, the correlation was not significant (r = 0.36, p = 0.08). The percentage difference between the dye-determined and directly measured amniotic fluid volume was significantly smaller in the women undergoing amniocentesis just prior to delivery (7%) than in the women with varying times from amniocentesis to delivery (37%, P < 0.001).
  
  
  CONCLUSIONS
  Dye-determined amniotic fluid volume accurately reflects actual amniotic fluid volume but the dye-determined concentrations, in vivo, may undergo rapid changes.
authors.affiliation: Department of Obstetrics and Gynecology, University of Mississippi Medical Center, Jackson, USA.
authors.forename: E F
authors.initials: EF
authors.lastname: Magann
authors.forename: N S
authors.initials: NS
authors.lastname: Whitworth
authors.forename: J C
authors.initials: JC
authors.lastname: Files
authors.forename: D A
authors.initials: DA
authors.lastname: Terrone
authors.forename: S P
authors.initials: SP
authors.lastname: Chauhan
authors.forename: J C
authors.initials: JC
authors.lastname: Morrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000618:Aminohippuric Acids; D000649:Amniocentesis / Q000379:methods; D000653:Amniotic Fluid / Q000000981:diagnostic imaging* / Q000502:physiology; D004395:Dye Dilution Technique; D005260:Female; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D012044:Regression Analysis; D016216:Ultrasonography, Prenatal / Q000379:methods*
chemical_list: D000618:Aminohippuric Acids