Sudden Infant Death Syndrome (SIDS)

What is SIDS?

Sudden Infant Death Syndrome (SIDS) is defined as the sudden death of an infant under one year of age that cannot be explained after a thorough case investigation, including a complete autopsy, examination of the death scene, and review of the clinical history. SIDS is the leading cause of death in infants between one month and one year of age. Most SIDS deaths occur between the ages of two and four months.

What are the causes?

Although researchers are still trying to understand what causes SIDS, the following are some important clues:

• Evidence suggests that some SIDS babies are born with brain abnormalities that make them vulnerable to sudden death during infancy. In many SIDS babies, abnormalities are found in parts of the brainstem that use serotonin as a neurotransmitter, and are thought to be involved in the control of breathing during sleep, sensing carbon dioxide and oxygen, and the ability to wake up. A baby with this abnormality may lack a protective brain mechanism that senses abnormal respiration or cardiovascular function and normally leads babies to wake up and take a breath.
  
• Babies who sleep on their stomach may get their faces caught in bedding, which causes them to breathe too much carbon dioxide and too little oxygen. Researchers are studying whether this is why sleeping on the stomach is hazardous and why babies with brainstem abnormality die when sleeping in this position.
  
• A larger number of babies who died from SIDS apparently had respiratory or gastrointestinal infections prior to their deaths. This fact may explain why more SIDS cases occur during the colder months of the year.
  
• Researchers indicate that some SIDS babies had higher-than-normal numbers of cells and proteins generated by the immune system. Some of these proteins interact with the brain to alter heart rate, slow breathing during sleep, or put the baby into a deep sleep, which may be strong enough to cause death, particularly if the baby has an underlying brain abnormality.

What are the symptoms?

There are no symptoms. Babies who die of SIDS do not appear to suffer or struggle.

What is the treatment?

Parents who have lost a child to SIDS are in tremendous need of emotional support. Because no cause is found for the infant's death, many parents suffer from guilt feelings.

These feelings may be aggravated by investigations in order to determine the cause of death. Timing of a subsequent pregnancy is a concern for many parents after experiencing SIDS. Family counseling may be recommended to help siblings and all family members cope with the loss of an infant.

Who is at risk for SIDS?