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

Abstract

Objective To systematically review the medical literature reporting on the prevalence of a niche 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 databases Medline and Embase were searched. All types of clinical studies reporting on the prevalence, risk factors and/or symptoms of a niche in non‐pregnant women with a history of Cesarean section (CS) were included. Case reports or case series were excluded. Results We selected 21 papers. A wide range in the prevalence of a niche was found. Using sonohysterography (SHG) in a random population of women with a history of CS, the prevalence varied 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 can be categorized into four categories: factors related to closure technique, development of the lower uterine segment or localization of the incision, wound healing and miscellaneous factors. Probable risk factors are single‐layer myometrium closure, multiple CSs and uterine retroflexion. Six out of eight studies 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 in four main categories, which may be useful for future research and meta‐analyses. The predominant symptom associated with a niche is postmenstrual spotting.