Surgery-related factors predisposing to uterine niche after cesarean section: a systematic review

Cesarean section is among the most common surgical procedures worldwide, with rates exceeding 48% in some European countries and continuing to rise for both primary and repeat cases. Multiple cesarean deliveries have become routine in many developed countries. This trend has increased the incidence of intrapartum and long-term complications, particularly cesarean scar defects, which are symptomatic in up to 40% of affected women. A cesarean scar defect, also known as a uterine niche or isthmocele, is one of the most critical conditions in modern obstetrics and gynecology, with continuously increasing prevalence, as 56%-84% of women who undergo cesarean section develop a niche. Judicious indication for cesarean delivery and an appropriate uterine suturing technique are key factors in minimizing post-cesarean complications, including uterine niches. Uterine niche epidemiology and risk factors are widely investigated with partially contradictory conclusions. In this systematic review, a detailed analysis of surgery-related factors connected to uterine niche formation is presented. Aspects of uterine suturing technique, including the number of suture layers, locked or unlocked suturing, inclusion of the endometrium, and the choice of suture material, are compared. The aspect of single- and double-layer uterine closure remains under debate, as most studies do not show the superiority of either technique with regard to uterine niche incidence. Optimizing the hysterotomy surgical technique may decrease the rate of cesarean scar defects and their complications, including pelvic pain, abnormal uterine bleeding, dyspareunia, placenta accreta spectrum disorders, and cesarean scar pregnancies. All patients undergoing cesarean delivery should be screened for cesarean scar defects and informed about the potential complications of cesarean section.