Formation of a uterine niche following a C-section can predispose the patient to future obstetric complications such as dehiscence, uterine rupture, ectopic pregnancy, and placenta accreta. The significant morbidity and mortality of these complications along with increasing C-section rates emphasizes the importance of prevention. However, there are no clear guidelines on intra-operative protocol to prevent postpartum niche formation. Besides surgical technique, the novel use of platelet-rich plasma (PRP) and mesenchymal stem cell (MSC) injections has demonstrated promising potential and may have applications in hysterotomy closures. The objective is to examine current research on optimal C-section procedures to prevent uterine niche formation and subsequent obstetric complications. A systematic review was conducted using PubMed and Google Scholar. Initial searches yielded 827 results. Inclusion criteria were human, animal, and in-vitro studies, peer-reviewed sources, and outcomes pertinent to the uterine niche. Exclusion criteria applied to articles with outcomes unrelated to myometrium and interventions outside of the intra-operative and immediate pre-/post-operative period. Based on the criteria, 41 articles were cited. Pathophysiology of uterine niche formation was associated with incisions through cervical tissue, adhesion formation, and poor approximation. Significant risk factors were low uterine incisions, advanced cervical dilatation, low station, non-closure of the peritoneum, and creation of a bladder flap. There was no consensus on uterine closure as it likely depends on surgical proficiency with the given technique, but a double-layered non-locking suture appears reliable to reduce niche severity. Recent trials indicate that intra-operative PRP/MSC injections may decrease niche incidence and severity, but more research is needed. If prevention or minimization of uterine niche is desired, the optimal C-section protocol should avoid low uterine incisions, choose uterine closure technique based on the surgeon\'s proficiency (double-layered non-locking is reliable), and close the peritoneum, and myometrial injection of PRP/MSC may be a useful adjunct intervention pending further clinical evidence.

Of all neonates, 21% are delivered by cesarean section (CS). A long-term maternal complication of an SC is a uterine niche. The aim of this review is to provide an overview of the current literature on imaging techniques and niche-related symptomatology. We performed systematic searches on imaging and niche symptoms. For both searches, 87 new studies were included. Niche evaluation by transvaginal sonography (TVS) or contrast sonohysterography (SHG) proved superior over hysteroscopy or magnetic resonance imaging. Studies that used SHG in a random population identified a niche prevalence of 42%-84%. Niche prevalence differed based on niche definition, symptomatology, and imaging technique. Most studies reported an association with gynecological symptoms, poor reproductive outcomes, obstetrical complications, and reduced quality of life. In conclusion, non-invasive TVS and SHG are the superior imaging modalities to diagnose a niche. Niches are prevalent and strongly associated with gynecological symptoms and poor reproductive outcomes.

The consequence of each cesarean section is the uterine scar formation. In some patients, uterine scar after cesarean section heals incompletely and as a result, the uterine niche is formed. Most of the small niches are asymptomatic, but the large cesarean scar niches in nonpregnant women may cause a cesarean scar syndrome, which manifest itself as abnormal uterine bleeding, dysmenorrhea and secondary infertility. Among pregnant women, the presence of large niches may be associated with potentially life-threatening consequences, such as cesarean scar dehiscence and uterine rupture, placenta accreta spectrum disorders, placenta previa, cesarean scar pregnancy. Due to the possibility of dangerous consequences related to the occurrence of a uterine niche, in recent years many studies have focused on the term of cesarean scar niche, its risk factors, diagnostic methods and treatment options. Uterine niche can be examined using two- or three-dimensional transvaginal ultrasonography, as well as two- and three-dimensional sonohysterography, hysterosalpingography, hysteroscopy or magnetic resonance imaging. However, neither of the above diagnostic method is considered as the \"gold standard\". There are no unambiguous guidelines on some aspect concerning the diagnosis of cesarean scar niche. The aim of this study is to analyze and describe the diagnostic methods of cesarean section niche.