Motherhood is marked by ambivalence, from its very beginning. Most studies that investigate the subjective experience of the mother have underlined the coexistence of mother?s love and hate, first in her relationship with the fetus, then the infant. The process of becoming a mother goes hand in hand with narcissistic investments and idealizations, in which maternal hostility usually manifests itself in unconscious forms. How the mother deals with this hostility beginning from her pregnancy plays a crucial role on the quality of the relationship between the mother and the infant. Projective tests and psychoanalytically-oriented clinical interviews are indispensable tools for understanding and studying unconscious processes of the mother. In this study, we will discuss how ambivalent emotions of the mother evolve throughout prenatal stages, first within a theoretical framework, then, by examining the interviews and tests of a longitudinal case, who has been followed since the first trimester of her pregnancy until the end of first year after the delivery.