a unique formation consisting of two living organisms (mother and child) that have common bodily and mental boundaries. It is a self-developing open structure with complex dynamics, regulated by presumably simple, but as yet unknown algorithms of interactions both within the dyad itself and the dyad with the environment as a whole. During the perinatal period, the prenate and then the infant lives almost the same life as the mother, and the dynamic structure of the surrounding world-mother-prenate is particularly sensitive to any fluctuations.