title: How reliable is the determination of cervical dilation? Comparison of vaginal examination with spatial position-tracking ruler.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the accuracy of clinical measurement of cervical dilation with a position-tracking system during vaginal examination.
  
  
  METHODS
  This prospective study that was conducted in Poissy, France, Brooklyn, NY, and Haifa, Israel, included 333 measurements that were performed in 188 women with term singleton vertex uncomplicated pregnancies during the active stage of labor. Ninety measurements with clinical diagnosis of full dilation were excluded from analysis. Measurements were performed with a sensor attached to the midwife's index fingertip and a position-tracking system that was based on a low magnetic field. Evaluations were done when cervical examinations were clinically indicated.
  
  
  RESULTS
  Results were similar in all centers. Mean error was 10.2 +/- 8.4 mm and ranged from 7.5 +/- 7.3 mm, when cervical dilation was > 8 cm, to 12.5 +/- 8.7 mm when cervical dilation was between 6.1 and 8 cm.
  
  
  CONCLUSIONS
  This first evaluation of cervical assessment accuracy during vaginal examination with a position-tracking system shows limited precision.
authors.affiliation: Department of Obstetrics and Gynecology, CHI Poissy Saint Germain, Université de Versailles, Saint-Quentin-en-Yvelines, France.
authors.forename: Jacky
authors.initials: J
authors.lastname: Nizard
authors.forename: Shoshana
authors.initials: S
authors.lastname: Haberman
authors.forename: Yoav
authors.initials: Y
authors.lastname: Paltieli
authors.forename: Ron
authors.initials: R
authors.lastname: Gonen
authors.forename: Gonen
authors.initials: G
authors.lastname: Ohel
authors.forename: Diane
authors.initials: D
authors.lastname: Nicholson
authors.forename: Yves
authors.initials: Y
authors.lastname: Ville