Diagnosis of fetal hypoxia

The predominant role in the overall pattern of perinatal mortality is currently played by antenatal fetal death (73%), the most considerable contribution to the pattern of which is made by chronic hypoxia. The pathophysiological processes of chronic fetal hypoxia are multicomponent and have not been fully explored. Its diagnostic methods used in obstetric practice have their limitations and disadvantages; they are often set up to register secondary or indirect signs, which cannot accurately predict severe neonatal outcomes or stillbirth. The most promising areas for research can be considered methods for the early diagnosis of placental insufficiency and noninvasive techniques for the functional assessment of fetal hypoxia, which is fundamentally important for initiating its maintenance therapy. This paper considers the general issues related to the pathophysiology of chronic hypoxia in the fetus and study methods for its assessment. It describes the new criteria for Doppler study, the widely used diagnostic method, which can assess the functional state of the fetal cardiovascular system in case of cardiac sparing and brain sparing effects. There are also the results of some pilot studies concerning the determination of specific hypoxia-induced RNA of the fetus in maternal blood, which have a high potential for the clinical biomarkers of obstetric complications. Attention is paid to a study method, such as MRI, the value of which will be able to significantly increase in the coming years. MRI allows a detailed study of the anatomical features of the placenta, identifying the causes of placental insufficiency. Furthermore, diffusion-weighted MRI (DW-MRI) or diffuse-tensor imaging (DTI) can provide additional functional information about the placenta, by detecting the areas of hypoperfusion. MRI also holds great promise to assess the fetal functional state: the markers of heart failure and lung tissue maturity are only part of new noninvasive fetal state imaging techniques that have the potential for further investigation and implementation in obstetric practice. Conclusion. Doppler blood flow study remains promising in the antenatal period; at the same time, great hopes are associated with MRI of placental insufficiency and the functional assessment of the fetal state, analysis of circulating fetal nucleic acids in maternal blood as markers of obstetric or fetal pathology.

chronic fetal hypoxia, fetal growth retardation syndrome, MRI diagnosis of placental perfusion, hypoxia- induced RNA of the fetus