title: Active-phase arrest in labor: predictors of cesarean delivery in a nulliparous population.
abstract: OBJECTIVE
  To identify clinical variables associated with cesarean delivery for active-phase arrest with hypotonic labor.
  
  
  METHODS
  We reviewed all deliveries at our institution from September 1975 through March 1989. Data were collected from medical records and a computerized data base. Nulliparas with active-phase arrest were identified and those with hypotonic labor (defined as less than 180 Montevideo units) were selected. The clinical characteristics of each parturient were examined. A linear logistic regression analysis was used to examine the incidence of cesarean delivery as a function of clinical variables.
  
  
  RESULTS
  The incidence of active-phase arrest was 4.9%, and hypotonic forces were diagnosed in 81% of the cases managed with an intrauterine pressure catheter. Despite the consistent use of oxytocin in hypotonic labor, the cesarean rate was 60%. Four factors correlated with cesarean delivery in this setting: estimated fetal weight, station at the time of arrest, duration of ruptured membranes, and year of delivery.
  
  
  CONCLUSIONS
  After an active-phase arrest, cesarean delivery increased when there was suspected cephalopelvic disproportion. In addition, we observed a strong correlation between cesarean delivery and the year of delivery, which suggests a change in physician behavior over time, independent of all other risk factors for cesarean.
authors: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California School of Medicine, San Francisco.
authors: V L
authors: VL
authors: Handa
authors: R K
authors: RK
authors: Laros
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007747:Labor Stage, First; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D010298:Parity; D011247:Pregnancy; D012044:Regression Analysis; D012307:Risk Factors