Background: Cesarean scar defect (CSD), also known as isthmocele or uterine niche, may be associated with abnormal uterine bleeding (AUB), postmenstrual spotting, dysmenorrhea, and dyspareunia. However, the relationship between sonographic CSD morphology and gynecologic symptoms remains inconsistent. This study evaluated the association between CSD dimensions and gynecologic symptoms in women undergoing transvaginal ultrasonography.
Methods: This two-center cross-sectional analytical study included women with confirmed CSD referred to Firoozabadi and Akbarabadi Hospitals, Tehran, Iran, from March 2025 to March 2026. CSD length, CSD depth, residual myometrial thickness (RMT), and adjacent myometrial thickness were measured by transvaginal ultrasonography. Symptoms, including irregular menstruation, postmenstrual spotting/AUB, severe AUB, dysmenorrhea, and dyspareunia, were recorded as binary outcomes. Statistical comparisons were performed using appropriate parametric or nonparametric tests, with P <0.05 considered statistically significant.
Findings: Among 207 women included in the final analysis, the mean age was 33.1±5.2 years. Mean CSD length, CSD depth, and RMT were 4.30±1.26 mm, 5.93±2.23 mm, and 4.38±2.04 mm, respectively. Postmenstrual spotting/AUB was reported in 78 women (37.7%), irregular menstruation in 71 (34.3%), severe AUB in 41 (19.8%), dysmenorrhea in 41 (19.8%), and dyspareunia in 35 (16.9%). RMT was significantly associated with irregular menstruation (P: 0.038), and CSD depth was significantly associated with postmenstrual spotting/AUB (P: 0.046). No significant associations were observed between measured CSD parameters and severe AUB, dysmenorrhea, or dyspareunia.
Conclusion: CSD depth and RMT may be more relevant to bleeding-related symptoms than pain-related symptoms. CSD morphology should be interpreted alongside clinical symptoms and other gynecologic factors.