Scientists now figure out why healthy babies have been dying in their sleep

Researchers from The Children’s Hospital Westmead in Sydney in an official study on sudden infant death syndrome (SIDS) say they now not only know how these infants die, but why. 

SIDS, which is commonly known as cot death, refers to the unexplained deaths of infants under a year old, and it usually occurs while the child is sleeping. 

Babies have been dying suddenly and unexpectedly for centuries.

In the First Book of Kings in the Old Testament, written about 500 BC, we read: “And this woman’s child died in the night; because she overlaid it”. 

For many centuries, overlying by the mother (causing suffocation) was accepted as the cause of sudden unexpected infant deaths. It was not until the late 18th century that doctors began to explore other possible causes for such deaths, beginning with the hypothesis that these infants suffered from an enlarged thymus, leading to “internal suffocation”.
This was widely accepted throughout the 19th century and indeed into the 1930s when it became discredited.

In 1969, a definition of the term Sudden Infant Death Syndrome was agreed upon at an international conference in the US.

“Many in the medical community suspected this phenomenon could be caused by a defect in the part of the brain that controls arousal from sleep and breathing. The theory was that if the infant stopped breathing during sleep, the defect would keep the child from startling or waking up,” the study observes. 

The Sydney researchers explain that they were able to confirm this theory by analysing dried blood samples taken from newborns who died from SIDS and other unknown causes. 

Each SIDS sample was then compared with blood taken from healthy babies. They found the activity of the enzyme butyrylcholinesterase (BChE) was significantly lower in babies who died of SIDS compared to living infants and other non-SIDS infant deaths. BChE plays a major role in the brain’s arousal pathway, explaining why SIDS typically occurs during sleep.  Previously, parents were told that SIDS could be prevented if they took proper precautions — laying babies on their backs, not letting them overheat and keeping all toys and blankets out of the crib were a few of the most important preventative steps. 

So, when SIDS still occurred, parents were left with immense guilt, wondering if they could have prevented their baby’s death.

According to Dr Carmel Harrington, the lead researcher for the study apart from being one of the parents, her son unexpectedly and suddenly died as an infant 29 years ago. 

In an interview with the Australian Broadcasting Corporation, Dr Harrington said: 

“Nobody could tell me the cause of death. They just said it’s a tragedy. But it was a tragedy that didn’t sit well with my scientific brain.” 

Since then, she’s worked to find the cause of SIDS, both for herself and for the medical community as a whole. She went on to explain why this discovery is so important for parents whose babies suffered from SIDS. 

“These families can now live with the knowledge that this was not their fault,” she believes.

The researchers add that the findings represent the possibility for the identification of infants at risk for SIDS prior to death and opens new avenues for future research into specific interventions.

As the cause is now known, they can focus on coming up with a permanent solution.

“In the next few years, those in the medical community who have studied SIDS will likely work on a screening test to identify babies who are at risk for SIDS and hopefully prevent it altogether,” the scientists say. 
 
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