title: Practice variation of vaginal birth after cesarean and the influence of risk factors at patient level: a retrospective cohort study.
abstract: BACKGROUND
  Large practice variation exists in mode of delivery after cesarean section, suggesting variation in implementation of contemporary guidelines. We aim to evaluate this practice variation and to what extent this can be explained by risk factors at patient level.
  
  
  METHODS
  This retrospective cohort study was performed among 17 Dutch hospitals in 2010. Women with one prior cesarean section without a contraindication for a trial of labor were included. We used multivariate logistic regression analysis to develop models for risk factor adjustments. One model was derived to adjust the elective repeat cesarean section rates; a second model to adjust vaginal birth after cesarean rates. Standardized rates of elective repeat cesarean section and vaginal birth after cesarean per hospital were compared. Pseudo-R2measures were calculated to estimate the percentage of practice variation explained by the models. Secondary outcomes were differences in practice variation between hospital types and the correlation between standardized elective repeat cesarean section and vaginal birth after cesarean rates.
  
  
  RESULTS
  In all, 1068 women had a history of cesarean section, of whom 71% were eligible for inclusion. A total of 515 women (67%) had a trial of labor, of whom 72% delivered vaginally. The elective repeat cesarean section rate at hospital level ranged from 6 to 54% (mean 29.8, standard deviation 11.8%). Vaginal birth after cesarean rates ranged from 50 to 90% (mean 71.8%, standard deviation 11.1%). More than 85% of this practice variation could not be explained by risk factors at patient level.
  
  
  CONCLUSIONS
  A large practice variation exists in elective repeat cesarean section and vaginal birth after cesarean rates that can only partially be explained by risk factors at patient level.
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Emy
authors.initials: E
authors.lastname: Vankan
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Ellen N
authors.initials: EN
authors.lastname: Schoorel
authors.affiliation: Department of Clinical Epidemiology and Medical Technology Assessment (KEMTA), Maastricht University, Maastricht, the Netherlands.
authors.forename: Sander M
authors.initials: SM
authors.lastname: van Kuijk
authors.affiliation: Department of Obstetrics and Gynecology, The Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Ben-Willem J
authors.identifier: http://orcid.org/0000-0001-8337-550X
authors.initials: BJ
authors.lastname: Mol
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Nijhuis
authors.affiliation: Department of Obstetrics and Gynecology, Zuyderland Medical Center, Sittard, the Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Aardenburg
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Marleen
authors.initials: M
authors.lastname: Alink
authors.affiliation: Department of Obstetrics and Gynecology, Hospital Rijnstate, Arnhem, the Netherlands.
authors.forename: Karin
authors.initials: K
authors.lastname: de Boer
authors.affiliation: Department of Obstetrics and Gynecology, Elkerliek Hospital, Helmond, the Netherlands.
authors.forename: Friso M C
authors.initials: FM
authors.lastname: Delemarre
authors.affiliation: Department of Clinical Epidemiology and Medical Technology Assessment (KEMTA), Maastricht University, Maastricht, the Netherlands.
authors.forename: Carmen D
authors.initials: CD
authors.lastname: Dirksen
authors.affiliation: Department of Obstetrics and Gynecology, Sint Jans Gasthuis, Weert, the Netherlands.
authors.forename: Ivo M
authors.initials: IM
authors.lastname: van Dooren
authors.affiliation: Department of Obstetrics and Gynecology, Groningen University Medical Center, Groningen, the Netherlands.
authors.forename: Maureen T M
authors.initials: MT
authors.lastname: Franssen
authors.affiliation: Department of Obstetrics and Gynecology, Röpcke-Zweers Hospital, Hardenberg, the Netherlands.
authors.forename: Mesrure
authors.initials: M
authors.lastname: Kaplan
authors.affiliation: Department of Obstetrics and Gynecology, Flevo Hospital, Almere, the Netherlands.
authors.forename: Gunilla
authors.initials: G
authors.lastname: Kleiverda
authors.affiliation: Department of Obstetrics and Gynecology, Catharina Hospital, Eindhoven, the Netherlands.
authors.forename: Simone M I
authors.initials: SM
authors.lastname: Kuppens
authors.affiliation: Department of Obstetrics and Gynecology, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: Anneke
authors.initials: A
authors.lastname: Kwee
authors.affiliation: Department of Obstetrics and Gynecology, Zuyderland Medical Center, Heerlen, the Netherlands.
authors.forename: Josje
authors.identifier: http://orcid.org/0000-0003-0107-2332
authors.initials: J
authors.lastname: Langenveld
authors.affiliation: Department of Obstetrics and Gynecology, IJsselland Hospital, Capelle aan den IJssel, the Netherlands.
authors.forename: Frans T
authors.initials: FT
authors.lastname: Lim
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Sonja
authors.identifier: http://orcid.org/0000-0001-6150-6783
authors.initials: S
authors.lastname: Melman
authors.affiliation: Department of Obstetrics and Gynecology, ZiekenhuisGroep Twente, Almelo, the Netherlands.
authors.forename: Marko J
authors.initials: MJ
authors.lastname: Sikkema
authors.affiliation: Caphri School for Public Health and Primary Care, Maastricht University, Maastricht, the Netherlands.
authors.forename: Luc J
authors.initials: LJ
authors.lastname: Smits
authors.affiliation: Department of Obstetrics and Gynecology, Tergooi Hospital, Hilversum, the Netherlands.
authors.forename: Harry
authors.initials: H
authors.lastname: Visser
authors.affiliation: Department of Obstetrics and Gynecology, Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands.
authors.forename: Mallory
authors.initials: M
authors.lastname: Woiski
authors.affiliation: Department of Obstetrics and Gynecology, GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center+, Maastricht, the Netherlands.
authors.forename: Hubertina C
authors.initials: HC
authors.lastname: Scheepers
authors.affiliation: Scientific Institute for Quality of Healthcare (IQ healthcare), Radboud University Nijmegen Medical Center, Nijmegen, the Netherlands.
authors.forename: Rosella P
authors.initials: RP
authors.lastname: Hermens
mesh_terms: D000328:Adult; D017604:Cesarean Section, Repeat / Q000706:statistics & numerical data*; D015331:Cohort Studies; D005260:Female; D006761:Hospitals / Q000706:statistics & numerical data; D006801:Humans; D015999:Multivariate Analysis; D009426:Netherlands / Q000453:epidemiology; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D014219:Trial of Labor; D016064:Vaginal Birth after Cesarean / Q000706:statistics & numerical data*
keywords: Cesarean section; practice variation; risk factors; trial of labor; vaginal birth after cesarean