Cot death. Conceptual computer artwork of an empty baby's cot. This could represent cot death or sudden infant death syndrome (SIDS). Although the cause of SIDS is not fully understood, most theories suggest abnormal breathing rhythms through respiratory infection, together with undetected inborn errors of metabolism, play an important role. Placing a baby to sleep on its back at the bottom of the cot should ensure uninhibited breathing for the child.