title: Amniotic fluid volume in normal pregnancy: comparison of two different normative datasets.
abstract: OBJECTIVE
  The aim of the present study was to compare the two normative datasets of amniotic fluid volume (AFV).
  
  
  METHODS
  The similarity of the two datasets to classify AFV as oligohydramnios, normal, and polyhydramnios based on fixed cut-offs, stratified by gestational ages (<24 weeks, 24-33(6/7), 34-36(6/7) , and >37 weeks, and to identify oligohydramnios/small for gestational age (SGA) and polyhydramnios/large for gestational age (LGA) was evaluated.
  
  
  RESULTS
  Of the 209 pregnancies assessed, the AFV was 94 ≤ 500 mL, 101 between 501 and 1999 mL, and 14 ≥ 2000 mL. The datasets were in agreement classifying the AFV as oligohydramnios, normal, and polyhydramnios in 76% of the pregnancies. Brace classified more overall patients with oligohydramnios (19%) versus Magann (3%) (P < 0.001). In term pregnancies (>37 weeks), Brace was more likely to classify pregnancies with oligohydramnios (15%) than Magann (3%) (P = 0.004). The likelihood ratio (LR) to detect oligohydramnios/SGA was greater with Magann (LR 12.9) versus Brace (LR 2.75).
  
  
  CONCLUSIONS
  The two datasets classify AFV differently in 24% of cases. Brace's dataset is more likely to categorize patients as having oligohydramnios and Magann's dataset is a more useful test for oligohydramnios/SGA identification.
authors.affiliation: Departments of Obstetrics and Gynecology, University of Arkansas for the Medical Sciences, Little Rock, Arkansas 72205, USA. efmagann@uams.edu
authors.forename: Everett F
authors.initials: EF
authors.lastname: Magann
authors.forename: Suneet P
authors.initials: SP
authors.lastname: Chauhan
authors.forename: Maureen
authors.initials: M
authors.lastname: Sanderson
authors.forename: Samantha
authors.initials: S
authors.lastname: McKelvey
authors.forename: Joshua D
authors.initials: JD
authors.lastname: Dahlke
authors.forename: John C
authors.initials: JC
authors.lastname: Morrison
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000502:physiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016104:Oligohydramnios / Q000000981:diagnostic imaging; D006831:Polyhydramnios / Q000000981:diagnostic imaging; D011247:Pregnancy; D014463:Ultrasonography