The article is devoted to the study of ultrasound changes in the fetoplacental complex in the early gestational period in pregnant womenwith miscarriage. Placental insufficiency (PI) is a syndrome caused by morpho-functional changes and is the result of a complex responseof the fetus and placenta to various pathological conditions of the maternal body [1]. It is based on disorders of compensatory-adaptivemechanisms of the fetoplacental complex (FPC) at the molecular, cellular and tissue levels. Ultrasound fetometry and placentometry are very important methods for diagnosing the state of the fetoplacental complex and can be used from the early term. Many researchers identify a number of prognostically unfavourable  ultrasound markers: low chorion attachment, especially with the appearance of areas of detachment, discrepancy between the size of the foetus and gestational age, lack of clear visualization of the embryo, especially its heartbeat. In pregnant women with a history of miscarriage it is important to identify early signs of placental dysfunction from the firsttrimester onwards and to provide adequate correction for this condition. For this situation it is important to create appropriate conditions for the development and growth of the placenta and its adequate functioning. Significant fetal abnormalities occur as early as the first trimester and have a significant impact on the further process of ontogenesis.Aims and objectives of the study. To assess the normal parameters of embryonic and extraembryonic formation and to evaluate theparticular features of the formation and development of the fetoplacental system during pregnancy in women with a history of miscarriage.Materials and Methods. We  erformed a comprehensive ultrasonographic examination of 25 somatically healthy women with aphysiological gestational process (control group) between 5 - 40 weeks’ gestation and 25 pregnant women with a history of miscarriage (study group). The SONOACE 8800 GAI MT with a 3.5 to 7.5 MHz convex transducer was used in the study. The data were statistically processed using standard methods of mathematical analysis with the use of Student’s and Fisher’s criteria, standard and specialized computer programs. Paired correlation indices were used to study the nature and degree of correlation between different parameters. The scientific research was positively evaluated by the Bioethics Commission of the Bukovinian State Medical University (Protocol No. 4 of  6.12.2021).Results and their discussion. In the transvaginal examination, uncomplicated pregnancy is characterized by the mandatoryvisualization of the embryo in the fetal cavity with a diameter of 14 mm or more, corresponding to 6 weeks' gestation. From the time of embryo identification in our study, we measured the coccygeal-parietal size (CPS) and compared its values with gestational age. It was found that in 22 (88.0%) cases the embryo size corresponded to the calculated gestational age and the mean inner diameter of the fetal egg. In severe clinical manifestations of threatened miscarriage the most sensitive echographic sign was a decrease in the volume of the foetus, which is a marker of further adverse pregnancy course and outcome. However, when there was an isolated increase in myometrial tone in the absence of clinical manifestations of threatened abortion, there was predominantly an isolated reduction in amniotic cavityvolume, easily corrected by the administration of conventional antispasmodic therapy.The ultrasonic criteria for alterations in pregnancy were developed, including delay in embryo CTR by 2 weeks or more on ultrasound examination up to 9 weeks' gestation; bradycardia at 90 bpm or less up to 8-12 weeks' gestation; chorionic detachment withretrochorial hematoma formation (over 25 ml); tachycardia at over 200 bpm with clinical manifestations of spontaneous miscarriage; marked progressive decrease of amniotic cavity volume; severe polyhydramnios with a thick echopositive suspension in the amniotic cavity. The risk of spontaneous miscarriage and formation of placental insufficiency increases with the simultaneous detection of 2 or more echographic markers.Conclusions. On the basis of the above, it is possible to conclude on the need to conduct an ultrasound examination with an assessment of the echographic parameters of the formation and development of the embryo and extraembryonic structures in the first trimester in pregnant women with a history of miscarriage and a risk of developing placental insufficiency in the history in order toidentify markers of a complicated course of gestation and the and the subsequent choice of rational tactics of pregnancy management.