Over the past decades, the frequency of cesarean section operations in the world has increased by 50%, and in the Russian Federation – by 10 times, and doctors are increasingly witnessing the formation of untenable scars on the uterus. The appearance of a scar on the uterus after cesarean section is inevitable, since smooth muscle tissue has a minimal ability to proliferate and regenerate after the damage. The frequency of occurrence of an untenable scar ranges from 19% to 86%, which is explained by the complexity of diagnosing this condition. The most common clinical manifestations of scar defect are abnormal uterine bleeding, chronic pelvic pain, dysmenorrhea, infertility; as well as an asymptomatic period that is often found. Currently, there is no common terminology and clear criteria and recommendations for assessing an untenable scar on the uterus. The only generally accepted is the Delphi international consensus, approved by European experts in 2019, but it is applicable only to the ultrasound assessment of the scar. The use of sonohysterography with saline solution is considered promising in diagnostics. The treatment is indicated in case of symptoms and a woman's desire to restore lost fertility. The possibilities of medication treatment of scar failure are very limited and insufficiently investigated. Modern research suggests performing a minimally invasive defect resection procedure as a first-choice operation. Currently, there is an active discussion about the preferred method of delivery in women with a scar on the uterus. Recent studies indicate that up to 75% of patients who have undergone cesarean section surgery can successfully undergo vaginal delivery. Successful vaginal delivery is associated with fewer complications than a repeated cesarean birth. Nowadays, the frequency of vaginal delivery in patients with a scar on the uterus in the Russian Federation does not exceed 1,5%. An additional study of the causes regarding formation of an untenable scar on the uterus and the improvements of therapeutic and diagnostic measures are required.