title: Short interpregnancy interval: risk of uterine rupture and complications of vaginal birth after cesarean delivery.
abstract: OBJECTIVE
  To investigate whether short or long interpregnancy interval is associated with uterine rupture and other major maternal morbidities in women who attempt vaginal birth after cesarean delivery (VBAC).
  
  
  METHODS
  We performed a secondary analysis of a U.S. multi-center, record-based, retrospective cohort study of 13,331 pregnant women, identified by a validated International Classification of Disease, 9th Revision, code search, with at least one prior cesarean delivery, who attempted VBAC between 1995 and 2000. We performed univariable and multivariable logistic regression analyses to evaluate the association between long or short interpregnancy interval and three maternal outcomes: 1) uterine rupture, 2) composite major morbidity (including rupture, bladder or bowel injury, and uterine artery laceration), and 3) blood transfusion. We evaluated short interpregnancy interval with cutoffs at less than 6, less than 12, and less than 18 months between prior delivery and conception and defined long interval as 60 months or more.
  
  
  RESULTS
  A total of 128 cases (0.9%) of uterine rupture occurred, and 286 (2.2%), 1,109 (8.3%), 1,741 (13.1%), and 2,631 (19.7%) women had interpregnancy intervals of less than 6, 6-11, 12-17, and 60 months or more, respectively. An interval less than 6 months was associated with increased risk of uterine rupture (adjusted odds ratio [aOR] 2.66, 95% confidence interval [CI] 1.21-5.82), major morbidity (aOR 1.95, 95% CI 1.04-3.65), and blood transfusion (aOR 3.14, 95% CI 1.42-6.95). Long interpregnancy interval was not associated with an increase in major morbidity.
  
  
  CONCLUSIONS
  Short interpregnancy interval increases risk for uterine rupture and other major morbidities twofold to threefold in VBAC candidates.
  
  
  METHODS
  II.
authors.affiliation: Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, Missouri 63110, USA. Stamiliod@wustl.edu
authors.forename: David M
authors.initials: DM
authors.lastname: Stamilio
authors.forename: Emily
authors.initials: E
authors.lastname: DeFranco
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Paré
authors.forename: Anthony O
authors.initials: AO
authors.lastname: Odibo
authors.forename: Jeffrey F
authors.initials: JF
authors.lastname: Peipert
authors.forename: Jenifer E
authors.initials: JE
authors.lastname: Allsworth
authors.forename: Erika
authors.initials: E
authors.lastname: Stevens
authors.forename: George A
authors.initials: GA
authors.lastname: Macones
mesh_terms: D000328:Adult; D002585:Cesarean Section; D015331:Cohort Studies; D005260:Female; D006801:Humans; D011247:Pregnancy; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D014219:Trial of Labor; D014597:Uterine Rupture; D016064:Vaginal Birth after Cesarean / Q000009:adverse effects*