title: Recurrent shoulder dystocia: analysis of incidence and risk factors.
abstract: OBJECTIVE
  To determine the rate and associated risk factors for recurrent shoulder dystocia (SD).
  
  
  METHODS
  A retrospective analysis was performed of patients delivered from January 1991 to June 2001. Patients with and without recurrent SD were identified and compared.
  
  
  RESULTS
  Among the 267,228 vaginal births during the study period, there were 1904 cases of SD (0.7%) and 270 patients with one additional vaginal birth. The recurrent SD rate was higher than the general population (3.7% versus 0.7%, odds ratio 7.36, 95% confidence interval 3.68 to 14.23, p < 0.001). Patients with recurrent SD had a slightly higher mean birth weight with the second delivery, but this difference was not statistically significant (4173 ± 544 g versus 4017 ± 577 g, p = 0.39).
  
  
  CONCLUSIONS
  Prior SD is a risk factor for recurrence in a subsequent delivery, but our results demonstrate that the rate appears to be lower than previously estimated. Most variables, including birth weight, do not appear to be useful parameters in predicting recurrence.
authors.affiliation: Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California, USA. jouzouni@usc.edu
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Ouzounian
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gherman
authors.forename: Suneet
authors.initials: S
authors.lastname: Chauhan
authors.forename: Leah R
authors.initials: LR
authors.lastname: Battista
authors.forename: Richard H
authors.initials: RH
authors.lastname: Lee
mesh_terms: D000328:Adult; D001724:Birth Weight; D003430:Cross-Sectional Studies; D036861:Delivery, Obstetric / Q000706:statistics & numerical data; D016640:Diabetes, Gestational / Q000453:epidemiology; D004420:Dystocia / Q000453:epidemiology*; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D011247:Pregnancy; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012782:Shoulder