title: Single versus double-layer uterine closure at cesarean: impact on lower uterine segment thickness at next pregnancy.
abstract: Uterine rupture is a potential life-threatening complication during a trial of labor after cesarean delivery. Single-layer closure of the uterus at cesarean delivery has been associated with an increased risk of uterine rupture compared with double-layer closure. Lower uterine segment thickness measurement by ultrasound has been used to evaluate the quality of the uterine scar after cesarean delivery and is associated with the risk of uterine rupture.
  
  
  
  To estimate the impact of previous uterine closure on lower uterine segment thickness.
  
  
  
  Women with a previous single low-transverse cesarean delivery were recruited at 34-38 weeks' gestation. Transabdominal and transvaginal ultrasound evaluation of the lower uterine segment thickness was performed by a sonographer blinded to clinical data. Previous operative reports were reviewed to obtain the type of previous uterine closure. Third-trimester lower uterine segment thickness at the next pregnancy was compared according to the number of layers sutured and according to the type of thread for uterine closure, using weighted mean differences and multivariate logistic regression analyses.
  
  
  
  Of 1613 women recruited, with operative reports available, 495 (31%) had a single-layer and 1118 (69%) had a double-layer closure. The mean third-trimester lower uterine segment thickness was 3.3 ± 1.3 mm and the proportion with lower uterine segment thickness <2.0 mm was 10.5%. Double-layer closure of the uterus was associated with a thicker lower uterine segment than single-layer closure (weighted mean difference: 0.11 mm; 95% confidence interval [CI], 0.02 to 0.21 mm). In multivariate logistic regression analyses, a double-layer closure also was associated with a reduced risk of lower uterine segment thickness <2.0 mm (odd ratio [OR], 0.68; 95% CI, 0.51 to 0.90). Compared with synthetic thread, the use of catgut for uterine closure had no significant impact on third-trimester lower uterine segment thickness (WMD: -0.10 mm; 95% CI, -0.22 to 0.02 mm) or on the risk of lower uterine segment thickness <2.0 mm (OR, 0.95; 95% CI, 0.67 to 1.33). Finally, double-layer closure was associated with a reduced risk of uterine scar defect (RR, 0.32; 95% CI, 0.17 to 0.61) at birth.
  
  
  
  Compared with single-layer closure, a double-layer closure of the uterus at previous cesarean delivery is associated with a thicker third-trimester lower uterine segment and a reduced risk of lower uterine segment thickness <2.0 mm in the next pregnancy. The type of thread for uterine closure has no significant impact on lower uterine segment thickness.
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université Laval, QC, Canada.
authors.forename: Chantale
authors.initials: C
authors.lastname: Vachon-Marceau
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université Laval, QC, Canada; Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Demers
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université Laval, QC, Canada; Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Bujold
authors.affiliation: Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Roberge
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gauthier
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC, Canada.
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Pasquier
authors.affiliation: Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.
authors.forename: Mario
authors.initials: M
authors.lastname: Girard
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Université Laval, QC, Canada; Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada.
authors.forename: Nils
authors.initials: N
authors.lastname: Chaillet
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Hôpitaux Universitaires de Genève, Université de Genève, Geneva, Switzerland.
authors.forename: Michel
authors.initials: M
authors.lastname: Boulvain
authors.affiliation: Department of Obstetrics & Gynaecology, Faculty of Medicine, Hôpitaux Universitaires de Genève, Université de Genève, Geneva, Switzerland. Electronic address: nicole.jastrowmeyer@hcuge.ch.
authors.forename: Nicole
authors.initials: N
authors.lastname: Jastrow
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects* / Q000379:methods*; D017604:Cesarean Section, Repeat / Q000009:adverse effects / Q000379:methods; D002921:Cicatrix / Q000517:prevention & control; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies; D014463:Ultrasonography; D014597:Uterine Rupture / Q000473:pathology; D014599:Uterus / Q000000981:diagnostic imaging / Q000473:pathology*; D058106:Wound Closure Techniques
keywords: cesarean; pregnancy; surgical technique; ultrasound; uterine scar