Prevalence, potential risk factors for development and symptoms related to the presence of uterine niches following Cesarean section: systematic review.

ABSTRACT

OBJECTIVE: To review systematically the medical literature reporting on the prevalence of a niche at the site of a Cesarean section (CS) scar using various diagnostic methods, on potential risk factors for the development of a niche and on niche-related gynecological symptoms in non-pregnant women. METHODS: The PubMed and EMBASE databases were searched. All types of clinical study reporting on the prevalence, risk factors and/or symptoms of a niche in non-pregnant women with a history of CS were included, apart from case reports and case series. RESULTS: Twenty-one papers were selected for inclusion in the review. A wide range in the prevalence of a niche was found. Using contrast-enhanced sonohysterography in a random population of women with a history of CS, the prevalence was found to vary between 56% and 84%. Nine studies reported on risk factors and each study evaluated different factors, which made it difficult to compare studies. Risk factors could be classified into four categories those related to closure technique, to development of the lower uterine segment or location of the incision or to wound healing, and miscellaneous factors. Probable risk factors are single-layer myometrium closure, multiple CSs and uterine retroflexion. Six out of eight studies that evaluated niche-related symptoms described an association between the presence of a niche and postmenstrual spotting. CONCLUSIONS: The reported prevalence of a niche in non-pregnant women varies depending on the method of detection, the criteria used to define a niche and the study population. Potential risk factors can be categorized into four main categories, which may be useful for future research and meta-analyses. The predominant symptom associated with a niche is postmenstrual spotting.