Cesarean Scar Niche and Pelvic Pain: A Systematic Review and Meta-Analysis

Pain is a long-accepted but inadequately explored symptom of cesarean scar niche (CSN) and it is important to systematic assess the prevalence and features of pelvic pain associated with CSN, also referred to as cesarean scar defect or isthmocele. The purpose of this study is to evaluate the association between CSN and pelvic pain.

A comprehensive strategy was used to search MEDLINE, EMBASE, Pub Med, Cochrane CENTRAL, and CINAHL from database inception to February 20th, 2025.

We included randomized controlled trials, prospective and retrospective cohorts, and case series involving symptomatic patients with a radiological diagnosis of CSN that evaluated pain as an outcome. Risk of bias was assessed with the Robins-I tool. The protocol was registered in PROSPERO (CRD42022346443).

The primary outcome was prevalence of pelvic pain in patients with confirmed CSN. Other outcomes included the risk of pain in patients with CSN compared those without, and changes in pain symptoms following medical or surgical management of niche. Sixty-four studies reported on pain (dysmenorrhea, dyspareunia, chronic pelvic pain (CPP), suprapubic pain (SPP)) in patients with CSN. Patients with a CSN were at increased risk of dysmenorrhea (RR: 2.25, 95% CI, 0.90-5.63), dyspareunia (RR: 2.06 95% CI, 1.42-2.99), and CPP (2.72, 95% CI, 1.63-4.54) compared to those without. In patients with confirmed niche, the prevalence of dysmenorrhea was 38.2% (95% CI 28.8-48.6); dyspareunia 28.2% (95% CI 15.3-46.0); CPP 26.8% (95% CI, 18.6-36.9) and SPP 32.5% (95% CI, 18.6-36.9). Both medical and surgical treatment of CSN significantly reduced pain symptoms (OR: 0.13, 95% CI, 0.08-0.23). Most studies were high risk for measurement bias due to lack of standardization for outcome measures.

There is a strong association between CSN and various pelvic pain symptoms. Future studies require standardization of nomenclature and reporting for pain in this context.