Sudden Infant Death Syndrome (SIDS)

Sudden infant death syndrome (SIDS), or ‘cot death’, is a form of sudden unexpected infant death (SUID) which involves the sudden and unexplained death of a seemingly healthy infant. This usually involves infants below the age of one year (most commonly below six months) and more often than not occurs while they are asleep.

According to the Centers for Disease Control and Prevention (CDC), SIDS accounted for about 37% of around 3,400 annual SUID cases in the United States in 2019, with unknown causes and accidental strangulation accounting for the remainder. In general, there has been an overall declining trend in global SIDS cases since the 1990s, with increasing awareness and conversations on how incidence may be prevented.


There are no apparent warning symptoms of SIDS. As the name denotes, it is ‘sudden’ and unexplained.


The cause of SIDS is as yet undetermined, although there is some speculation that it might be linked to a specific developmental phase in the infant that makes them more vulnerable to environmental stresses in terms of how they regulate their breathing, temperature and heart rate. There are a few risk factors that scientists have been able to associate with the condition. These include:

  • premature birth
  • lower than normal birth weight
  • environmental stresses such as exposure to tobacco smoke, getting tangled in bed linen, obstruction to breathing
  • slight minor illness


There is no definite means of preventing the incidence of SIDS as cause and nature may vary from one case to another. However, based on observations and autopsy studies done over the years, there are certain measures that can be taken to reduce the risk of SIDS, at least to some extent. As such:

  • infants should always be placed in a supine position (i.e., on their back) to sleep, until the age of one year
  • infants should be made to sleep on a firm, flat, waterproof mattress that fits snugly in a safety-approved crib
  • the infant’s cot should ideally be placed in the same room as the parents and within close proximity to the parents’ bed for up to at least the first six months, but ideally up to one year of age – this is considered to be the safest sleeping arrangement
  • all sheets should be well-fitted, with no loose bedding, soft toys, loose pillows or comforters around the infant
  • infants should ideally be placed with their feet touching the end of the cot and their blanket tucked in no higher than their shoulder level, with their heads uncovered at all times
  • seating such as car seats and strollers should not be used for regular sleep
  • sleeping with a parent on a couch or armchair and co-sleeping on a bed should be avoided
  • bed-sharing should be particularly avoided if either parent smokes or consumes alcohol or drugs, or is sedated for some reason
  • the area above and around the cot should be clear of any loose cords or wiring that could cause strangulation
  • if an infant is taken to be breastfed during the night, they should be returned to their cot and tucked in on a supine position to sleep again once again
  • a room temperature of between 16oC to 20oC is considered to be an ideal and comfortable sleeping environment for infants – i.e., not too hot or cold
  • mothers should receive regular prenatal care in order to minimise the risk of complications during pregnancy and at birth
  • mothers should refrain from smoking and consuming alcohol or drugs, and should maintain a healthy diet during pregnancy and after giving birth (particularly for as long as they breastfeed)
  • exposure of pregnant mothers as well as infants to tobacco smoke in any form should be avoided (including second hand smoking and infants sleeping in the same room as a smoker)
  • infants should be administered with the recommended vaccinations after birth in order to increase their immunity against infection and disease
  • breastfeeding should be encouraged, unless not possible for medical or biological reasons, as it is strongly associated with boosting infant immunity and is believed to have protective effects against the incidence of conditions such as SIDS
Compiled image of what is considered to be a safe sleep environment for an infant
Image from TOTS Family

Practising such recommended measures and attentively monitoring an infant within their first year of life would largely contribute towards their overall health and safety as they progress into childhood and beyond.

It is probably equally worth mentioning here that although parents of infants are advised to be attentive and careful with their children, in many cases, the incidence of SIDS cannot be prevented due to its sudden and unpredictable nature. It is therefore important that these parents are given sufficient emotional support and clarity so as to prevent or minimise potentially harmful thoughts of self-blame from arising.

Cover illustration adapted from iStock

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