title: Duration of labor by gestational week in nulliparous women.
abstract: OBJECTIVE
  To assess whether labor length differs by week of gestation.
  
  
  METHODS
  In this observational cross-sectional study, we compared duration of labor by gestational age (36 + 0 through 40 + 6 weeks) in primiparous singleton parturients with vertex presentation. Data were acquired for a period of 24 months (2010-2011).
  
  
  RESULTS
  In general, the rate of change in cervical dilatation decreased as gestational week at delivery advanced: 1.8 ± 1.0 cm/h, 1.5 ± 0.9 cm/h, 1.3 ± 0.8 cm/h, 1.6 ± 1.5, and 1.3 ± 1.0 cm/h at 36th, 37th, 38th, 39th and 40th gestational week, respectively (p = 0.040). Concurrently, the total labor duration (1st + 2nd + 3rd stages) increased as gestational age advanced: 423.6 ± 180.9 min, 496.5 ± 212.6 min, 545.9 ± 247.1 min, 483.8 ± 256.3 min, and 568.2 ± 273.8 min at 36th, 37th, 38th, 39th and 40th gestational week, respectively (p = 0.013).
  
  
  CONCLUSIONS
  Gestational week of pregnancy may alter the duration of labor, specifically, the length of labor increases as gestational week at delivery advances.
authors.affiliation: Department of Obstetrics and Gynecology, Edith Wolfson Medical Center , Holon , Israel .
authors.forename: Samuel
authors.initials: S
authors.lastname: Lurie
authors.forename: Yana
authors.initials: Y
authors.lastname: Vinnikov
authors.forename: Mona
authors.initials: M
authors.lastname: Boaz
authors.forename: Abraham
authors.initials: A
authors.lastname: Golan
authors.forename: Oscar
authors.initials: O
authors.lastname: Sadan
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007743:Labor, Obstetric / Q000502:physiology*; D010298:Parity; D011247:Pregnancy