title: Reproducibility of measuring amniotic fluid index and single deepest vertical pool throughout gestation.
abstract: OBJECTIVE
  The aim of this study is to assess the intraobserver and interobserver reproducibility of measurement of amniotic fluid index (AFI) and single deepest vertical pool (SDVP), also known as the maximal vertical pocket.
  
  
  METHODS
  A total of 175 fetuses were evaluated. For each fetus, two observers acquired duplicate sets of AFI and SDVP. Measurement differences were expressed as actual and percentage values. For all comparisons, Bland-Altman plots were used to compare differences, and limits of agreement were calculated.
  
  
  RESULTS
  Intraobserver and interobserver agreement remained fairly constant with gestation, both for AFI and SDVP. The intraobserver limits of agreement for AFI were -5.2 to 5 cm or -39% to 37%; whereas for SDVP, these were -2.6 to 2.4 cm or -52% to 48%. The interobserver limits of agreement for AFI measurement were -7.3 to 7.1 cm or -54% to 53% and for SDVP measurement were -2.5 to 2.5 cm or -51% to 52%. Intraobserver coefficient of variation for SDVP was 14% and for AFI was 19%; the interobserver coefficient was 19% for both AFI and SDVP.
  
  
  CONCLUSIONS
  Limits of agreement for both methods are wide. The choice of method should be dictated by clinical considerations other than method reproducibility.
authors.affiliation: Department of Radiology, Aga Khan University Hospital, Nairobi, Kenya; Oxford Maternal & Perinatal Health Institute (OMPHI), Green Templeton College and Nuffield Department of Obstetrics and Gynecology, John Radcliffe Hospital, University of Oxford, Oxford, UK.
authors.forename: J A
authors.initials: JA
authors.lastname: Sande
authors.forename: C
authors.initials: C
authors.lastname: Ioannou
authors.forename: I
authors.initials: I
authors.lastname: Sarris
authors.forename: E O
authors.initials: EO
authors.lastname: Ohuma
authors.forename: A T
authors.initials: AT
authors.lastname: Papageorghiou
mesh_terms: D000328:Adult; D000653:Amniotic Fluid / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015588:Observer Variation; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D011446:Prospective Studies; D015203:Reproducibility of Results; D016216:Ultrasonography, Prenatal / Q000379:methods*