title: Fetal head-symphysis distance and mode of delivery in the second stage of labor.
abstract: OBJECTIVE
  To evaluate whether the fetal head-symphysis distance measured by three-dimensional transperineal ultrasound during the active second stage predicts operative delivery.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  University hospital, Bologna, Italy.
  
  
  METHODS
  Seventy-one nulliparous women at term in active second stage of labor.
  
  
  METHODS
  We acquired a series of sonographic volumes at the beginning of the active second stage (T1) and every 20 min thereafter (T2, T3, T4, T5, T6) until delivery. All volumes were retrospectively analyzed and head-symphysis distance was measured for each acquisition. We compared head-symphysis distance between women with spontaneous vaginal delivery and those with operative delivery. Receiver operator characteristic curves were constructed to estimate the accuracy of head-symphysis distance in the prediction of operative delivery. Logistic regression was used to identify independent variables associated with operative delivery.
  
  
  METHODS
  Operative delivery (vacuum or cesarean).
  
  
  RESULTS
  Of the women included, 81.7% had a spontaneous vaginal delivery and 18.3% underwent operative delivery. Women with spontaneous vaginal delivery had shorter head-symphysis distance than women in the operative delivery group at T1 (p < 0.001), T2 (p < 0.001) and T3 (p = 0.025), whereas no significant differences were recorded thereafter. Receiver operator characteristic curves revealed accuracy values of 81.0%, 87.9% and 77.6% in the prediction of operative delivery at T1, T2 and T3, respectively. At multivariate logistic regression head-symphysis distance and epidural analgesia were the only independent predictors of operative delivery among ultrasonographic, maternal and intrapartum variables.
  
  
  CONCLUSIONS
  Ultrasonographic measurement of head-symphysis distance in the second stage of labor can be used to predict operative delivery.
authors.affiliation: Department of Obstetrics and Gynecology, Sant'Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.
authors.forename: Aly
authors.initials: A
authors.lastname: Youssef
authors.forename: Elisa
authors.initials: E
authors.lastname: Maroni
authors.forename: Luisa
authors.initials: L
authors.lastname: Cariello
authors.forename: Federica
authors.initials: F
authors.lastname: Bellussi
authors.forename: Elisa
authors.initials: E
authors.lastname: Montaguti
authors.forename: Ginevra
authors.initials: G
authors.lastname: Salsi
authors.forename: Antonio Maria
authors.initials: AM
authors.lastname: Morselli-Labate
authors.forename: Alexandro
authors.initials: A
authors.lastname: Paccapelo
authors.forename: Nicola
authors.initials: N
authors.lastname: Rizzo
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Pilu
authors.forename: Tullio
authors.initials: T
authors.lastname: Ghi
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data*; D005260:Female; D005323:Fetal Monitoring / Q000379:methods / Q000706:statistics & numerical data; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007558:Italy / Q000453:epidemiology; D007746:Labor Presentation; D007748:Labor Stage, Second / Q000502:physiology*; D009321:Natural Childbirth / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology; D011446:Prospective Studies; D018570:Risk Assessment; D016216:Ultrasonography, Prenatal / Q000379:methods / Q000706:statistics & numerical data; D014620:Vacuum Extraction, Obstetrical / Q000706:statistics & numerical data*
keywords: Fetal head-symphysis distance; intrapartum; labor; three-dimensional; ultrasound