The changes associated with the development of new reproductive technologies, and notably of IVF that currently account for more than 1% of births in France, have been the subject of many studies, but few have conducted a longitudinal analysis of the trajectories of the couples engaged in an IVF course of treatment. This largely unexplored field is approached here through the observation of one thousand medical files of a hospital service that provides medically assisted conception. The study describes the types of itineraries followed by couples from first consultation for infertility to an eventual in vitro fertilization, and attempts to identify some of the social compromises that shape the process. Against a background of growing demand for technological solutions, clinical constraints and specific strategies of the couples, the study highlights the dominant role of the medical institution and the influence of the patients in the social construction of these trajectories.