SIDS: causes
By definition, the causes of SIDS are not known. Attempts to explain the sudden and unexpected death of an infant adequately have been difficult since earliest times. Initially, if a baby died suddenly and unexpectedly in a bed shared with adults, it was thought to be due to an adult rolling on to the infant during sleep. This was called ‘over-laying’.
Later, it was suggested that babies may have choked on something or that death was caused by parental neglect. It is clear now that in most cases, none of these explanations were correct – that they were, in all probability, the victims of what is now known as SIDS.
What are the warning signs?
No consistent warning signs occur that might alert us to the risk of SIDS. Sometimes the infant was not feeding quite so well on the day he or she died, or there may have been symptoms of a slight cold or tummy upset. It seems that while minor infections of some sort or another are almost always found in SIDS babies, on careful post-mortem examination these infections are mild and seem in themselves to be an inadequate cause of sudden death. While we do not yet know the causes and mechanism of death, we do know that SIDS is not contagious.
Is smothering a cause of SIDS?
If the baby was found face down or with bedclothes over the face, it might be thought that smothering was the cause of death. Sometimes babies are covered by bedclothes, but others are found uncovered and free of bedclothes entirely.While it is possible for an infant to smother accidentally, this is rare. Not uncommonly the child is lying undisturbed, as when last put to bed, without any possible interference to breathing. In some cases blood-tinged froth is found around the mouth or on the bedding. This fluid comes from the lungs, which are always very congested in a child dying of SIDS. Sometimes vomiting has occurred, but when the postmortem examination is carried out, there is little or no inhaled food in the windpipe. These are normal occurrences during or soon after death, and do not cause the death.
Most SIDS deaths appear to happen quietly in sleep.Many of the infants are found in exactly the same position as they were when put to bed. Others may have moved but there is no indication that they go through any prolonged period of pain or distress. Facial or body discolouration may occur but this is caused by the position after death and will normally fade in a day or so.
Last Reviewed: 01 December 2003
