Background: Cesarean section complications are becoming more common as cesarean scar defects.
Objective: This study aimed to evaluate the anatomical characteristics of cesarean scar niche by diagnostic hysteroscopy and sonohysterography in women with unexplained secondary infertility.
Patients and methods: This observational cross-sectional study included 100 women who attended our outpatient clinic, complaining of unexplained secondary infertility with a history of at least one CS and showing scar niche in office hysteroscopy followed by re-assessment by saline infusion sonohysterography with the evaluation of scar depth, width, and shape in both methods.
Results: The present work revealed that 45 cases had unhealthy (fibrotic) scars, 41 cases had collected blood in the niche, 24 cases had infected scars, 5 cases had endometritis, and 4 cases had a small submucosal polyp, as well as one case, had a small uterine septum. There were 32 cases with post-menstrualspotting, the mean duration of post-menstrualspotting was 2.5 days (±0.9 SD), 19 cases had chronicpelvic pain, 15 cases had both post-menstrualspotting and chronic pelvic pain, 12 cases had dyspareunia. There were 25, 31, and 44 cases that had 2ry infertility  ≥ 1, ≥ 2, and ≥ 3 years respectively. There was a non-significant correlation between features of the niche through diagnostic hysteroscopy and correlated symptoms.
Conclusion: Cesarean scar may play an intermediate role in fertility. Hysteroscopy is considered the golden standard tool for the diagnosis of different intrauterine lesions, however; the procedure of sonohysterography is well-tolerated, cost-effective, and can be performed in an office-based gynecological practice, and doesn't require special training.