BACKGROUND: Worldwide caesarean section rates have risen from around 7% in 1990 to 21% today, and are projected to continue increasing over this current decade. If this trend continues, by 2030 the highest rates are likely to be in Eastern Asia (63%), Latin America and the Caribbean (54%), Western Asia (50%), Northern Africa (48%) Southern Europe (47%) and Australia and New Zealand (45%), the research suggests.

Methods:This prospective observational study was conducted on women with previous cesarean section or more at the department of Obstetrics and Gynecology at Minia Maternity and Children University Hospital through the period from March 2021 to March 2023.patient should be 18 to 40 years old aged non-pregnant females who had previous cesarean section or more with abnormal uterine bleeding, offensive vaginal discharge, pelvic pain and secondary infertility Patients were assessed post menstrual. All suspected women with scar niche are subjected first to Transvaginal ultrasonography 2D to detect if niche present or not but 25 cases are excluded because they haven't enough data about previous caesarean section then Transvaginal ultrasonography 2D saline sonohysterography then Transvaginal ultrasonography 3D saline sonohysterography followed by hysteroscopy as gold standard for detection scar niche in another appointment .

Results: 2DSHG has 91.7% sensitivity and 94.4% specificity with 92.7% accuracy for detection of niche while 3DSHG has 98.9% sensitivity and 98.1% specificity with 98.7% accuracy for detection of niche.