This paper examines the way in which paediatricians manage in the case of neo-natal resuscitation to make the decision to continue or stop the procedures, and this within a context characterised by the lack of reliability on scientific norms. The authors aimed to highlight that which orients the medical decisions in a local context of uncertainty. The data have been extracted from a significantly sized field project (based on observations and interviews) carried out in two neo-natal intensive care service units.