title: Long-term complications of caesarean section. The niche in the scar: a prospective cohort study on niche prevalence and its relation to abnormal uterine bleeding.
abstract: OBJECTIVE
  To study the prevalence of niches in the caesarean scar in a random population, and the relationship with postmenstrual spotting and urinary incontinence.
  
  
  METHODS
  A prospective cohort study.
  
  
  METHODS
  A teaching hospital in the Netherlands.
  
  
  METHODS
  Non-pregnant women delivered by caesarean section.
  
  
  METHODS
  Transvaginal ultrasound (TVU) and gel instillation sonohysterography (GIS) were performed 6-12 weeks after caesarean section. Women were followed by questionnaire and menstruation score chart at 6-12 weeks, 6 months, and 12 months after caesarean section.
  
  
  METHODS
  Prevalence of a niche 6-12 weeks after caesarean section, using TVU and GIS.
  
  
  RESULTS
  relation to postmenstrual spotting and urinary incontinence 6 and 12 months after caesarean section; and niche characteristics, evaluated by TVU and GIS.
  
  
  RESULTS
  Two hundred and sixty-three women were included. Niche prevalence was 49.6% on evaluation with TVU and 64.5% with GIS. Women with a niche measured by GIS reported more postmenstrual spotting than women without a niche (OR 5.48, 95% CI 1.14-26.48). Women with residual myometrium at the site of the uterine scar measuring <50% of the adjacent myometrial thickness had postmenstrual spotting more often than women with a residual myometrial thickness of >50% of the adjacent myometrial thickness (OR 6.13, 95% CI 1.74-21.63). Urinary incontinence was not related to the presence of a niche.
  
  
  CONCLUSIONS
  A niche is present in 64.5% of women 6-12 weeks after caesarean section, when examined by GIS. Postmenstrual spotting is more prevalent in women with a niche and in women with a residual myometrial thickness of <50% of the adjacent myometrium.
authors.affiliation: Department of Obstetrics and Gynaecology, Deventer Hospital, Deventer, the Netherlands.
authors.forename: L F
authors.initials: LF
authors.lastname: van der Voet
authors.forename: A M
authors.initials: AM
authors.lastname: Bij de Vaate
authors.forename: S
authors.initials: S
authors.lastname: Veersema
authors.forename: H A M
authors.initials: HA
authors.lastname: Brölmann
authors.forename: J A F
authors.initials: JA
authors.lastname: Huirne
mesh_terms: D000328:Adult; D002585:Cesarean Section / Q000009:adverse effects*; D002921:Cicatrix / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008796:Metrorrhagia / Q000453:epidemiology*; D009215:Myometrium / Q000000981:diagnostic imaging; D011247:Pregnancy; D015995:Prevalence; D011446:Prospective Studies; D014463:Ultrasonography
keywords: Abnormal uterine bleeding; caesarean section; caesarean section scar; niche; postmenstrual spotting; ultrasonography