title: Impact of labor at prior cesarean on lower uterine segment thickness in subsequent pregnancy.
abstract: OBJECTIVE
  The objective of the study was to identify the factors associated with sonographic lower uterine segment (LUS) thickness near term in women with prior low transverse cesarean.
  
  
  METHODS
  A prospective cohort study of women with a single prior low transverse cesarean was conducted. LUS thickness was quantified by transabdominal ultrasound with repeated transvaginal measurement when necessary. The thinnest measurement was considered as the dependent variable. Potential related factors were evaluated with nonparametric analyses and multivariate logistic regressions.
  
  
  RESULTS
  Two hundred thirty-five women were recruited at a mean gestational age of 36.7 +/- 1.3 weeks. The full LUS was thicker in women who had their previous cesarean during the latent phase (2.8 mm; interquartile [IQ], 2.0-3.3 mm) or the active phase of labor (3.1 mm; IQ 2.5-3.9 mm) than in women with previous cesarean prior to labor (2.4 mm; IQ 2.0-3.2 mm). The association remained significant after adjustment for potential confounders.
  
  
  CONCLUSIONS
  Presence of labor at previous cesarean is associated with a thicker LUS in a subsequent pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Faculty of Medicine, Hôpital Sainte-Justine, Université de Montréal, Montréal, QC, Canada.
authors.forename: Nicole
authors.initials: N
authors.lastname: Jastrow
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gauthier
authors.forename: Geneviève
authors.initials: G
authors.lastname: Gagnon
authors.forename: Nathalie
authors.initials: N
authors.lastname: Leroux
authors.forename: Francois
authors.initials: F
authors.lastname: Beaudoin
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bujold
mesh_terms: D000328:Adult; D002585:Cesarean Section; D005260:Female; D005865:Gestational Age; D006801:Humans; D007743:Labor, Obstetric; D011247:Pregnancy; D011446:Prospective Studies; D014463:Ultrasonography; D014599:Uterus / Q000000981:diagnostic imaging*; D016064:Vaginal Birth after Cesarean