Objective: to evaluate changes in the morphology of scar tissue tissues after cesarean section with unfavorable perinatal outcomes in the consecutive pregnancy. Materials and methods. A morphological study of a resected scar on the uterus after a previous cesarean section was performed. The main group (n=28) included samples of scar tissues of patients in case of unfavorable perinatal outcomes; the comparison group (n=32) included biological samples of 32 pregnant women at birth of healthy newborns with an Apgar score of 7 or more points and no signs of physiological immaturity and fetal growth retardation. Results. In case of unfavorable perinatal outcomes significantly more often uneven and/or weak blood filling of the microvasculature was determined (p=0,0483 and p=0,0492 respectively) in the area of scar tissue regarding to the group of women at the birth of healthy children. In contrast, the comparison group is characterized by a significantly larger number of sections with neoangiogenesis (p=0,0452). The most significant difference in the histological pattern of the scar tissue of the comparison groups was the presence of moderate diffuse intermuscular stroma edema: in 85,7% of the samples of the main group and in 56,3% of the comparison group (p=0,0173). Conclusion. It can be assumed that the formation of placental dysfunction with an outcome of unfavorable perinatal outcomes in patients with a scar on the uterus after cesarean section is preceded by a violation of the formation of an adequate uterine structure in the scar area due to local microcirculation dysfunction.