Fetal hypoxia is a condition characterized by a reduced oxygen supply of fetal tissues. Although fetal hypoxia can be caused by many factors, it usually occurs due to progressive placental insufficiency and is associated with intrauterine growth restriction. In a state of fetal hypoxia, adaptation mechanisms are activated, and bloodstream centralization occurs, which is beneficial to the fetal brain (brain sparing effect), heart, and adrenal glands, while the periphery remains deprived of adequate amounts of oxygen. It is important to emphasize that diagnostic tools for measuring blood flow redistribution in favor of the fetal brain have been developed, and their bases are Doppler indices of the umbilical and middle cerebral arteries. Monitoring of the Doppler indices, particulary cerebroumbilical ratio, is the most important prenatal diagnostic tool for the prognosis of neurodevelopmental disorders. New findings are based on the fact that functional and structural brain damage occurs even in stable hemodynamic compensatory mechanisms, so the brain sparing effect is not considered to be an entirely physiological response. The consequences of fetal hypoxia and intrauterine growth restriction can be periventricular leukomalacia, intracranial bleeding, and a wide range of functional neurological damage. Therefore, research in modern perinatal medicine should be based on finding a new high-quality diagnostic tests or using a combination of the existing ones to allow early diagnosis of potentially endangered fetuses and define the time of delivery. This would prevent perinatal brain damage and its long-term effects on the health of children.