The participation of women in prenatal care, their adherence to orientations and the way they will take care of their children involve a myriad of social interests and possibilities. As a result, both investing in ways of control and managing the way they will gestate, give birth, feed and take care of their children become important. Such way of exerting power over life has not only been supported by either the medical or political discourse; it has also required an articulation of discursive practices that are taught and reproduced by a social complex involving the media, health professionals and the pregnant women’s families. This paper has stemmed from an intervention-research in which conversation workshops were carried out with pregnant women receiving prenatal care at a philanthropic hospital. Here, we analyze what has been regarded as a social norm of what means to be a “good mother”, by understanding such norm as a device intended to govern families.