[Sudden death in new-born babies (author's transl)].

This sudden death of a new-born baby, which had been thriving up to then, is a dramatic but not exceptional event. A systematic search for the etiology must be made, and this should include an autopsy in order that the diagnosis of "sudden and unexplained death" is confirmed only after eliminating all other possible causes. Knowledge of this syndrome has benefited from epidemiological surveys which have defined the previous clinical condition, but none of the many etiollotical hypotheses envisaged can take into account the total number of cases reported. One of the most recent cases developed apnoea during sleep, which could explain some unexpected deaths in new-born babies. This was discovered by polygraphic sleep recordings and confirmed by pathological examinations. These demonstrated indirect signs of chronic hypoxia which could have been related to the sudden death of the baby. Though there does not appear to be any relationship between the apnoea syndrome during sleep and these sudden and unexpected deaths, this hypothesis has opened up a new promising line of research which could help to identify new-born babies at risk from "sudden death", and to propose preventative measures.