The incidence of unintentional childlessness in women who have, as popular comment puts it, 'left it too late', is rising markedly in many western nations, yet the experience is not well understood. This thesis focuses on issues of fantasy, loss, and grieving in the experience of 26 New Zealand women in their 30s and 40s who are what Cannold (2005) has termed 'circumstantially childless'; that is women who expected to have children but find themselves at the end of their natural fertility without having done so for - at least initially - social rather than biological reasons. I explore the conscious and unconscious dimensions of the fantasies that many of the women interviewed have about themselves as mothers in relation to a child or children. I argue that these fantasies have their origins in these women's trans-subjective relationship with their mothers before birth, the intersubjective relationship after birth, and the mutual overlapping of their unique psychobiography and the social worlds in which they have become adults. Circumstantial childlessness entails a loss of the potential to embody their fantasies about themselves as mothers. The thesis uses psychoanalytic and contemporary grief theories to explore their experience of loss and grieving, and their adaptation of their fantasies when the potential to embody them has passed. It calls for a reconceptualization of maternal subjectivity to encompass the creative and satisfying alternative ways that women who do not have children embody 'mother' in their lives. The study's psychoanalytically-informed psychosocial methodology entailed the innovative use of participant-produced drawings, and the development of a method of recording protocols - based on Bollas'(2007) notion of a symphonic score - to systematically record non-linguistic elements of the texts (such as sighs, hesitations, laughter, repetitions, and tears) across the range of the semi-structured individual and group interview transcripts. In this respect, the thesis contributes to investigations of social life that move beyond the limits of conventional text-based methods of inquiry and interpretation.