BACKGROUND: Growth disturbances are common in pregnancies complicated by pregestational diabetes mellitus. Identifying the relationship between the structural and functional characteristics of the placenta and abnormal fetal growth is important for understanding its formation and the possibility of its prediction. AIM: The aim of this study was to conduct a comparative analysis of the postnatal morphological and prenatal ultrasound features of the structure of placentas in cases of fetal growth disorders in pregnant women with pregestational diabetes mellitus. METHODS: In this retrospective single-center cohort study, we analyzed the results of the morphological studies of 1200 placentas, including those with fetal growth disorders in pregnant women with pregestational diabetes mellitus. Ultrasound prenatal fetometry, placentometry and Doppler measurements were used in this study. The studied placentas were weighed, with their size and cotyledonous structure assessed. Placental histopathological parameters were diagnosed using standardized criteria. Statistical analysis was carried out using SPSS Statistics version 23.0. RESULTS: The comparison groups included patients with pregestational diabetes mellitus types 1 and 2 with the absence (n = 394) or the presence of various fetal growth disturbances such as fetal growth restriction (n = 109), small (n = 118) and large (n = 352) for gestational age fetuses. The control group (n = 157) consisted of pregnant women with normal fetal growth rates and normal carbohydrate metabolism. In the placentas from pregnant women with pregestational diabetes mellitus, regardless of the presence of fetal growth disorders, we identified a number of distinctive features compared to patients in the control group. These were abnormal size, inconsistency of the structure of the placenta and the gestational age with a predominance of dissociated villous maturation, the presence of circulatory disorders of varying degrees, the presence of inflammatory changes in the placenta, deposition of calcium salts, and the development of chronic placental insufficiency and placental infarction. Moreover, in pregestational diabetes mellitus, the placentas of fetuses with macrosomic and normal growth often demonstrated similar features of the morphological structure. In intrauterine growth restriction, signs of pathological immaturity, premature and abnormal maturation of the villi prevailed in the structure of the placenta, with sclerosis of the villous stroma, placental infarctions, and circulatory disorders being more common. We demonstrated an association of grade II and III hemodynamic disorders with the features of maturation and structure of the villi and the presence of placental insufficiency. Critical blood flow disorders in the umbilical artery were associated with severe circulatory disorders in the placentas. CONCLUSION: In analyzing the morphofunctional and ultrasound characteristics of the placenta in cases of fetal growth disorders in pregestational diabetes mellitus, we found changes associated with both impaired carbohydrate metabolism and the influence of concomitant conditions. Some features of placental morphology in pregestational diabetes mellitus appeared to be morphofunctional adaptations. A relationship was found between fetoplacental hemodynamics Doppler disturbances and the histological structure of the placentas.