Objectives The aim of the article is to present the psychological dynamics of natural childbirth. The main issue is the phenomenon of psychical regression as a process that facilitates the experience and the course of delivery. Using the theory of Melanie Klein, the author presents the progress of regression during particular phases of labor, the contributory factors and inpediments. The predominant state in labor is the paranoid-schizoid one, because of the threat of women’s physical and psychical borders. The regression comes to the point of the fusion with the mother and the symbiosis with the child, what symbolically and emotionally become the reversion to the intra-uterine life. This shift enables women to experience the labor with comparative equanimity and inner self-confidence as well as with reduced pain sensation. The author describes, the dynamics of parturient’s aggression, connected with paranoid-schizoid state, and the crucial role of handling this aggression by professionals. Both, the obstacles in regression and inefficacy of handling aggression of childbearing women are the main psychological determinants that disturb the process of labor. The factors facilitating regression are intimacy during the time and in the place of childbirth as well as successful identification with the mother. The myth of the Greek goddess of childbirth –Eileithyia -was used as to illustrate, in a symbolic manner, the discussed matter.