title: Correlation of measured amniotic fluid volume and sonographic predictions of oligohydramnios.
abstract: OBJECTIVE
  To compare the measured volume of amniotic fluid (AF) in term gestations to the volume predicted sonographically.
  
  
  METHODS
  One hour before elective cesarean delivery, 40 women had sonographic measurement of the AF index and largest vertical pocket diameter. At surgery, a suction catheter was placed into a 1-cm uterine incision and a second catheter was used to aspirate AF from the operative field. Hemoglobin concentration was measured in the collected AF to determine the extent of blood contamination.
  
  
  RESULTS
  The mean measured AF volume was 532 mL (range 40-1692). The correlation coefficient between AF index and AF volume was 0.744 (P < .001). A similar value (r = 0.755, P < .001) was observed for the largest vertical pocket measured with ultrasound.
  
  
  CONCLUSIONS
  Sonographic measurements of the largest vertical pocket and the AF index have similar positive correlations with measured AF volumes at term. Current methods of estimating AF volume have low sensitivity for detecting oligohydramnios.
authors.affiliation: Department of Obstetrics and Gynecology, University of Texas Southwestern Medical School, Dallas.
authors.forename: R
authors.initials: R
authors.lastname: Horsager
authors.forename: L
authors.initials: L
authors.lastname: Nathan
authors.forename: K J
authors.initials: KJ
authors.lastname: Leveno
mesh_terms: D000653:Amniotic Fluid; D002585:Cesarean Section; D005260:Female; D006801:Humans; D016104:Oligohydramnios / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011237:Predictive Value of Tests; D011247:Pregnancy; D012680:Sensitivity and Specificity; D016216:Ultrasonography, Prenatal