Cot Death, more correctly defined as Sudden Infant Death Syndrome (SIDS), has been with us over the ages. The first reference to it is in the Bible (Kings 3:19) "... and this woman's child died in the night because she overlaid it." Because infants until this century normally slept in their parents bed, the assumption was that sudden unexpected deaths were due to suffocation by overlaying. By the nineteenth century medical experts were beginning to question this assumption and a variety of theories began to emerge, none of which, however, produced any clear answer to the puzzle.
In 1969, at an international conference on sudden infant death, the following definition was proposed for the term Sudden Infant Death Syndrome. "The sudden death of an infant or young child, which is unexpected by history, and in which a thorough post mortem examination fails to demonstrate an adequate cause for death". By 1971 the Registrar General and the Coroners' Society of England and Wales accepted the Syndrome as a certifiable cause of death and it is now widely used, although the term "Cot Death" is more common in the United Kingdom.

Until 1991 the rate in Scotland was approximately 2 per 1,000 livebirths, similar to the rate in other developed countries. Since then the rate has gradually deceased and is now around 0.7 per 1,000 livebirths, a drop also noted in other parts of the world. Although we cannot be certain of the cause of this decrease, it is probable that avoiding placing babies on their fronts to sleep has made a major contribution.

In the typical case an apparently healthy infant is put down to sleep without the slightest suspicion that anything is out of the ordinary, although there are sometimes signs of a slight cold. When next checked the infant is dead.
Sometimes the time interval is only minutes. Sometimes the baby has not even been sleeping - there are accounts of infants dying in the middle of a feed. There is no sound or sign of a struggle, or of any distress.

Although the basic cause(s) of Cot Death are unknown there are certain characteristics which have been confirmed by a large number of different studies.
Age Distribution
Cot Death is relatively uncommon in the first month of life. Thereafter the incidence rapidly rises, reaching a peak in the third and fourth months. 83% of Cot Deaths occur in the first six months and only about 5% in babies aged 9-12 months. A very small number of Cot Deaths - 3-4% - take place in the second year of life.
Sex Incidence
There is a clear sex difference in SIDS with a male:female ratio of approximately 1.6:1.0. This far outweighs the small excess of male births (1.05:1.0) and is in sharp contrast to the sex incidence in non-SIDS postperinatal infant deaths which affect a roughly equal number of boys and girls.
Seasonal Incidence
Cot Death is more common in winter than in summer - approximately twice the number of deaths occur in the three winter months compared to the three summer months.
Birth Order
Second and later born infants are at greater risk than the first born.
Maternal Age
Young mothers (under 20 years old) are more likely to lose a baby to Cot Death than older mothers, particularly if the baby is a second or later born. For example, the risk of SIDS in a second born baby may be seven times greater if the mother is under 20 than if the mother is aged 25 or over.
Obstetric Factors
Preterm, low birth weight babies are more likely to die from Cot Death than infants in the general population, as are twins. There have been clearly documented accounts of twins both dying during the same sleep period.
Soci-Economic Factors
Cot Death is more common with deprivation but occurs in families at all social levels. There is unanimous agreement that maternal smoking is an increased risk, particularly during pregnancy, resulting in a seven-fold risk when the mother smokes 20 cigarettes per day. Smoking by parents and other household members after the baby is born also increases the risk. The infants of drug-abusing mothers are more vulnerable to Cot Death.
Infant Care Practices
There is now considerable evidence that placing babies to sleep on their fronts increases the risk of Cot Death. Side sleeping also appears to be less safe than back. Overheating may put a baby at more risk. Breastfeeding does not appear to provide protection from Cot Death, although it is advised for other reasons.

Many theories have been put forward over the years and research has been carried out in the fields of pathology. physiology, epidemiology and risk reduction. A few cases of sudden, unexpected death have been found to be the result of infant botulism and inherited metabolic disorders but no single theory for Cot Death has yet been proved and many have been discounted. It is anticipated that no single area of study will provide the final solution but each may ultimately contribute to the understanding of the mechanism of these deaths.

Since we do not know why Cot Deaths occur, we cannot prevent them. However, research has indicated that the risks may be reduced if the following steps are taken:-
1. To place the baby to sleep on its back.
2. To avoid smoking during pregnancy and after birth to keep the baby in a smoke-free room.
3. To avoid overheating the baby.
4. To consult a doctor if the baby seems unwell.

Any sudden, inexpected death is devastating. If we add to this the facts that the death is that of a baby, and that no explanation can be given, it is not difficult to imagine the problems facing the bereaved family.
In Scotland when a Cot Death occurs it is routinely reported to the Procurator Fiscal - as is the case with any sudden unexpected death - and the Fiscal will order a police investigation and a post mortem examination. While these are an inevitable part of our legal system and may, in fact, give a "certificate" of innocence to the parents, they can be distressing. Equally distressing and bewildering is the lack of an explanation for the death.
Because Cot Death occurs unexpectedly and usually at home, almost every parent feels some degree of responsibility. Families have been broken up by repercussions arising from a lack of knowledge about Cot Death. It is important, therefore, to emphasise that Cot Death is unforeseen, therefore unpreventable, and that these babies often belong to the most careful, loving parents. It has often been noted how well cared for most Cot Death babies are. Occasionally a baby has been seen by the family doctor shortly before death, because of some slight ailment, such as a cold. Nothing has been found that would have indicated a need for serious concern or have led anyone to anticipate a sudden death.
Sometimes parents fear that their baby has suffocated or choked. There is no evidence that suffocation is a factor in Cot Death and parents need to be reassured about this. Cot Death is also not caused by vomiting and choking. Sometimes milk or blood-tinged froth is found around the mouth or nose. This occurs after death and on post mortem examination the fluid is not found to have blocked the internal air passages.

Parents naturally fear a recurrence. However, Cot Death is not hereditary and any future babies in the family will run only a very slight risk of recurrence, of the order of 2-5 times the population rate.

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