In an attempt to illustrate the relevance of psychoanalytic theory and research to behavior medicine, an empirical investigation was conducted of females treated at a high-risk pregnancy specialty clinic (N = 58). Drawing from psychoanalytic object relations theory, it was hypothesized and confirmed that use of projection as a defense mechanism during pregnancy, superimposed on simplistic object relations, predicted an erosion of patient-provider relationships during the pregnancy/postdelivery period. Findings are interpreted through the perspective of mentalization, pertaining to individuals' ability to understand the mental states of self and others, specifically under significant stress. Implications for psychoanalytically oriented assessment and treatment, and for the rift between psychoanalysis and research, are discussed.