[Morphology of the cerebral cortex in fetuses and extremely low weight newborns in normal pregnancy and miscarriage of hormonal etiology].

Complex histologic, histostereometric and electron microscopic study of fields 4 and 6 of the brain cortex in fetuses and newborns with an extremely low body weight allowed to specify formation of histoarchitectonics of the motor analyser during the second trimester of perinatal ontogenesis. Stages of differentiation (20-23 weeks) and maturation (24-27 weeks) of neurons and cytoarchitectonic layers of the motor zone in uncomplicated pregnancy as well as slow maturation of this cortex region in incomplete pregnancy of hormonal genesis were discovered. In this condition, there are lengthening of the neuron differentiation stage up to 26 weeks of gestation and important reduction of histostereometrical values (thickness of individual cytoarchitectonic layers and that of all the cortex) and cytokaryometrical values (volume of neuron nuclei) as compared to those in uncomplicated pregnancy.