ABSTRACT

Objective

Objective To study the prevalence of niches in the caesarean scar in a random population, and the relationship with postmenstrual spotting and urinary incontinence.Design A prospective cohort study.Setting A teaching hospital in the Netherlands.Population 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.Main outcome measures Prevalence of a niche 6-12 weeks after caesarean section, using TVU and GIS. Secondary outcomes: 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.Keywords Abnormal uterine bleeding, caesarean section, caesarean section scar, niche, postmenstrual spotting, ultrasonography.Please cite this paper as: van der Voet LF, Bij de Vaate AM, Veersema S, Brölmann HAM, Huirne JAF. 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. BJOG 2014;121:236-244.

Incomplete healing of the scar is a recognized sequel of Cesarean section (CS) and may be associated with

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