This study indicates the need to explicit the different rationalities which make themselves present within the process of health care and which are constituted, on one hand, by the assertion of contrai, and, on the other hand, by the unexplicited reproductive decisions of clients, consubstantiated by the "unexpected advent/emergence of pregnancy''.Furthermore, it is necessary to recognize the autonomy of people living with HIV/Aids with respect to reproductive decisions so that these may occur within circumstances involving fewer risks. In arder for this to occur, it is necessary to understand the different rationalities present within the contexts in which reproductive decisions are made as well as those in which the norms involving the contrai of the HIV/Aids epidemic are defined and put into practice.