A Systematic Review on Caesarean Niche and Postmenstrual Spotting Syndrome: The Scar That Speaks.

The global increase in caesarean section rates has intensified concern about long-term gynaecological outcomes. Among these, the caesarean scar defect, also known as isthmocele or niche, has emerged as a notable cause of postmenstrual spotting, abnormal uterine bleeding, and infertility. Despite its clinical relevance, diagnostic criteria and management strategies remain heterogeneous and poorly standardised. This systematic review synthesised existing evidence on the association between caesarean scar defects and postmenstrual spotting, while also describing commonly used diagnostic approaches, symptom profiles, and reported management outcomes. Comprehensive searches of major medical databases were undertaken, with records managed in EndNote X9 and findings synthesised narratively. Across the literature, postmenstrual spotting was the predominant manifestation, frequently accompanied by pelvic pain, dysmenorrhoea, and infertility. Hysteroscopic resection was the most widely reported intervention, with most reports describing improvement in bleeding patterns and related symptoms, whereas laparoscopic and vaginal repairs were more often used in women with thin residual myometrium or fertility concerns and were associated with favourable reproductive outcomes. Overall, the evidence base was moderate in quality, limited by small sample sizes and clinical heterogeneity. Caesarean scar defects show a strong association with postmenstrual spotting and related morbidity, underscoring the need for standardised diagnostic definitions and well-designed prospective studies to guide clinical practice.