title: Accuracy and intraobserver variability of simulated cervical dilatation measurements.
abstract: OBJECTIVE
  Our purpose was to assess the accuracy and intraobserver variability of clinical cervical diameter measurements among obstetric health care providers.
  
  
  METHODS
  Polyvinyl chloride pipes 1 to 10 cm in diameter were mounted in cardboard boxes and used to simulate cervical examinations. The boxes were designed so that the examiner had to rely solely on proprioception to determine the inner diameter.
  
  
  RESULTS
  A total of 1574 simulated cervical diameter measurements were obtained from 102 different examiners in a two-part study. The overall accuracy for determining the exact diameter was 56.3%, which improved to 89.5% when an error of +/- 1 cm was allowed. Intraobserver variability for a given diameter measurement was 52.1%, which decreased to 10.5% when an error of +/- 1 cm was allowed.
  
  
  CONCLUSIONS
  Cervical diameter measurements obtained by digital examination are precise when an error of +/- 1 cm is allowed for. Intraobserver variability is > 50% and is an important consideration when evaluating dysfunctional labor.
authors.affiliation: Department of Obstetrics and Gynecology, Brooke Army Medical Center, San Antonio, Texas, USA.
authors.forename: J Y
authors.initials: JY
authors.lastname: Phelps
authors.forename: K
authors.initials: K
authors.lastname: Higby
authors.forename: M H
authors.initials: MH
authors.lastname: Smyth
authors.forename: J A
authors.initials: JA
authors.lastname: Ward
authors.forename: F
authors.initials: F
authors.lastname: Arredondo
authors.forename: A R
authors.initials: AR
authors.lastname: Mayer
mesh_terms: D002584:Cervix Uteri / Q000033:anatomy & histology* / Q000502:physiology*; D005260:Female; D006801:Humans; D008954:Models, Biological; D015588:Observer Variation; D009774:Obstetrics / Q000592:standards; D011247:Pregnancy