What Causes Sudden Infant Death Syndrome?

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What Causes Sudden Infant Death Syndrome?

What Causes Sudden Infant Death Syndrome?Cot or crib death has been with us for centuries, but for many of those years, it has been disguised by superstition and mystery. It was only in 1969 that it was recognized as a distinct condition — mainly coupled with suffocation as result of overlaying or bed-sharing. Since then, there have been many theories on the causes – some ranging from hereditary factors to environmental causes.

Yet, even though potential causes are investigated to exhaustion, no isolated direct cause has been found to date.


What is Sudden Infant Death?

Today Sudden Infant Death Syndrome (SIDS) is described as an unexpected death, usually during sleep of an otherwise seemingly healthy baby. Because the exact cause or causes are unknown, leading scientists like Prof Hannah Kinney from the Havard School of Medicine (Pathology) have been researching SIDS for the past 20 years. Kinney links SIDS with abnormalities in the portion of the infant’s brain that controls breathing and arousal from sleep. She maintains that SIDS is due to a developmental brainstem defect in autonomic and/or respiratory control during sleep. Kinney and her associates are determined to define brainstem abnormalities in the living infant and to suggest ways to prevent these abnormalities from eventually leading to SIDS.

Certain sleep environments are likely to increase the risk of SIDS in already vulnerable babies. As a result, parents are encouraged to arm themselves with information that will help them protect their infant.


Important Research Findings

The U.S Library of Medicine has a trusted base of health research information. Recent information by their paediatric collaborators state that SIDS is the leading cause of death in children between three weeks and one year, with the biggest incidence occurring between two and four months.

According to researchers:

  • Abnormal brainstems do not cause SIDS abnormality in new born babies.
  • A toxic gaseous poisoning could play a role in the neurological outcome of nerve gas-poisoning.
  • The incidence of SIDS raises with birth order, i.e. from first to second babies, second to third babies, etc.
  • Highest incidence is found among solo parents, thus the cause cannot be physiological. The cause could be an imbalance in the way the brain uses the neurotransmitter known as serotonin.
  • The New England Research Institute in Massachusettes, USA recommends avoiding multiple and simultaneous SIDS risks (both intrinsic and extrinsic factors).

Dr TJ Sprott, a leading author, chemist and forensic scientist, confirmed Kinney’s findings in the Journal of Neuropathy and Experimental  Neurology 1997, stating that:

  • In children’s deaths relating to neurological causes — decreased kainite receptor bindings were found. These were linked to the inhalation of Carbon Dioxide (CO2).
  • Dr Sprott maintained that carbon dioxide or toxic gas generated by mattress wrappings is a risk factor for SIDS and the risk rises as the mattress is reused by the next sibling.

Experts in New Zealand (2009) have reviewed the mattress theory and maintain that there is not enough evidence to support the claim that toxic fumes from the chemical reaction between bed-wetting and a flame retardant chemical (animony), cause SIDS. However, since the mattress wrapping protocol was announced in New Zealand in 1990’s, SIDS deaths reduced by 70%. The advice is therefore is to avoid old mattresses and prevent any foam or padding to be exposed for bacterial risks.


Interesting statistics on SIDS

  • SIDS is higher for the poor regardless of race.
  • Sweden had the lowest incidence of SIDS in 2008.
  • The Netherlands had the lowest and Japan the second lowest incidence in 2005. A review of Japan’s statistics in 2011 showed a continued lowering.
  • New Zealand and the USA had the highest and second highest incidence respectively, as noted in 2005.
  • Compared to developed countries, the US incidence of SIDS remains high (2011).
  • South Africa’s incidence of SIDS is ranked seventh highest in the world relative to 53 nations.
  • New findings show that breast-feeding reduces the odds of SIDS by half.
  • Pre-mature babies have a higher risk.


Reduce risk factors by:

  • Placing an infant on his back for safe sleep. Tummy-time is for when baby is awake and when somebody is watching. An infant’s sleep positions pose suffocation risks.
  • Using a firm surface as crib mattress as well as a fitted sheet. Nothing else should go in the crib.
  • Keeping loose bedding and soft objects away from the sleeping area. (No blanket, pillow, bumper pads or toys should be in the crib to free the baby from any entrapment).
  • Seeing that your baby is not too hot. A comfortable temperature (optimal at 67 degrees F(same as that of an adult).
  • Seeing that the total sleeping environment is safe and the baby protected.
  • Keeping up with research and baby lifestyle product manufacturers and suppliers.
  • Acquiring baby products like a mattress which is approved by a consumer and product safety standards councils.
  • Purchasing an electronic alarm application which is triggered when a baby stops breathing.  The alarm set-off brings immediate help to aid the infant, although there is no guarantee.
  • Asking your pediatrician for the latest findings and campaigns (e.g. breastfeeding and bed-sharing) on SIDS.
  • Follow strategies for prevention campaigns for maternal smoking.
  • Avoiding acute food-poisoning induced by a product such as botulin. Honey proved at times to contain bacteria causing botulin.
  • Making sure agricultural products are clean, peeled and well-cooked.
  • Preventing the infant from exposure to excessive temperature.
  • Washing clothes in hot water and ironing them to get rid of bacteria and allergens.
  • Providing a breathable environment especially in the case of bronchial congestion by elevating the head with a cushion under the mattress. Air the space by a ventilation flow to the face-down (vertical).



Could bed-sharing and a non-standard bed underlie in part, cause a SIDS death? Is sleeping with a baby in an adult bed unsafe and can it lead to accidental smothering?

Researchers agree that it is difficult to scientifically pronounce a practice like bed-sharing as a cause of SIDS  or as safe, as there are so many variations in sleeping patterns, age, size, types of beds, etc. which essentially makes it difficult to answer this question.


Safety measures

To be as safe as possible:

  • Avoid sleeping with the baby if you are under the influence of a drug or tranquilizers. Medicine and alcohol diminishes your sensitivity to the baby’s presence.
  • Extreme obesity causes apnea in the mother and smothering and overlaying can be dangerous.
  • If deprived of sleep a person is less aware.
  • Use a co-sleeper or crib-like bed that fits safely adjacent to a parent’s bed. It gives both mother and child sleeping space and ease to reach for nighttime care.
  • Take precautions to prevent baby rolling out of the bed. A body gravitates towards a warm body though.
  • It is better to place a baby adjacent to the mother rather than between the mother and father who might not be as sensitive to the baby’s presence. One should be physically and mentally aware of the baby’s in sleep-sharing.
  • Use a large bed like a king or queen size bed. Make sure there is no crevice the baby can sink into and the mattress is flush against the wall on the baby’s side.
  • Safe-sleeping campaigns recommend that an infant sleeps in the same room as parents up to 12 months.
  • Some parents and babies sleep better if the baby is still touching and in hearing distance but not in the same bed.
  • Make the babysitter aware of safety measures as they may not be as acute as the mother.
  • No older siblings are to sleep with a baby of under 9 months old.
  • Do not lay a baby on any uneven surface such as a couch as it can suffocate by wedging between the back of the couch and the larger person’s head.
  • Do not to wear lingerie with string ties longer than 200 mm or jewellery which can be caught in an entrapment while you are sleep-sharing with your baby.
  • Do not overheat or over-bundle your baby. Warm bodies add heat.
  • Avoid pungent sprays that camouflage the natural maternal smell. It could irritate or clog the baby’s nasal passages.
  • Use common sense when sleep-sharing.
  • Bed-sharing proves beneficial as it increases the mother’s awareness and also has emotional benefits.
  • Co-sleeping in Japan is not uncommon while their SIDS incidence is lowering. Their bedrooms contain fewer risks like a low bed and simple firm mattresses.

Most of the above research information is confirmed by the Mayo Foundation for Medical Education and Research (US) (a non-profit organization).

Dr Hannah Kinney who is best known for her triple risk hypothesis, claims that not all SIDS victims are normal. Until 1952, SIDS was regarded as normal but according to Kinney, it is not normal and arises from brain abnormalities which she postulated “to originate in-utero leading to death during a vulnerable post-natum period.” Kinney’s study was first reviewed in 2002 and published in a Journal of The US National Library of Medicine (Pediatrics). Kinney emphasizes pre-natal injury of the brainstem and continues her research to prove her theory.


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