Definition Sudden infant death syndrome (SIDS) is the sudden, unexpected death of an infant under 1 year of age. No cause for the death can be found after a thorough investigation. The investigation includes a complete autopsy, an examination of the death scene, and a review of the medical history.
What is going on in the body? SIDS is a tragic, unfortunate event that has probably been a part of the human experience for thousands of years. SIDS is the leading cause of death for babies between the ages of 1 month to 1 year. In Australia, an average of five babies die each week as a result of this problem.
Researchers have been looking for the cause of SIDS for at least 35 years. While some risk factors have been identified, the key cause is unknown. Current research is looking into problems with an infant's breathing and heart rate. There may be subtle differences in the areas of the brains of SIDS victims that regulate the heart and breathing. It is possible that there may be several different causes of SIDS.
What are the signs and symptoms of the condition? There are no warning symptoms of SIDS. Often infants have symptoms of a chest cold or a stomach virus in the days before their death. Most infants who die of SIDS appear normal when put to bed.
What are the causes and risks of the condition? There are known risk factors for SIDS. These have come from research. None of these factors clearly point to a distinct cause for SIDS. Many of these factors are also risk factors for the sudden death of infants from explained causes. Risk factors associated with a higher incidence of SIDS include:
age of the child. Most cases occur in infants between 2 to 4 months of age. Ninety-five percent of cases occur in infants 6 months of age or younger.
male sex. Boys are victims slightly more often than girls.
prematurity, or being born early, or having a low birth weight
low Apgar score at birth. This is a measure of how well an infant adapts to life outside the womb in the first 5 minutes after birth.
being part of a multiple birth, such as twins or triplets
a baby that sleeps on his or her stomach, is wrapped in blankets during sleep, sleeps on a soft surface, or sleeps with others in the same bed or crib
a baby who has had a recent viral illness, or is exposed to tobacco smoke
In addition, research has found risk factors in the mother that may lead to an increased incidence of SIDS. These may include a mother who has inadequate antenatal care, is unmarried, young, poor, and smokes during pregnancy and after the birth of the child. Also, a mother who uses illicit drugs, especially cocaine, during pregnancy, is at higher risk of having a baby die from SIDS. Other risk factors include having pregnancies less than 12 months apart or having had a large number of pregnancies.
What can be done to prevent the condition? Because the cause or causes of SIDS are not known, there is no known prevention for all cases of SIDS. Eliminating risk factors should reduce the number of SIDS deaths. This has already happened. In theory, changing behaviour based on other known risk factors may also reduce the incidence of SIDS. Some possible changes that could be helpful in preventing SIDS include:
providing universal, accessible, affordable antenatal care to all pregnant women beginning early in pregnancy
finding effective ways to teach teens to be sexually responsible and to avoid pregnancy
finding effective ways to prevent teens from beginning to smoke or to help them quit
educating pregnant women about the dangers of illicit drug use during and after pregnancy
educating parents to avoid other risks of SIDS, such as teaching them not to wrap infants in blankets and not to let infants sleep on their stomachs
Attempts to prevent SIDS by the use of heartbeat and breathing monitors in the home have not been found to be effective and are rarely used.
How is the condition diagnosed? The diagnosis of SIDS is by an autopsy examination that excludes other specific causes for an infant's death. In order to establish the diagnosis of SIDS, the autopsy must be thorough and done by an expert in infant death.
The diagnosis of SIDS is established if no other causes of death can be found and the autopsy findings are compatible with SIDS.
What are the long-term effects of the condition? The long-term effects of SIDS include feelings of guilt, sadness, and anger in the parents.
What are the risks to others? There are no risks to others as this condition is not contagious.
What are the treatments for the condition? There is no treatment for the infant because the diagnosis can be made only after death. Support groups or counselling may be advised for the parents.
What happens after treatment for the condition? Parents must deal with the grief of losing a child.
How is the condition monitored? Parents of an infant who dies of SIDS often experience shock, grief, and guilt. They often feel that there is something they may have done to cause it or could have done to prevent it. It is important for friends and relatives who are close to the family, as well as professionals involved with the family, to be compassionate. Support and empathy are needed. Accusations should be avoided. While a small percentage of unexplained infant deaths are due to child abuse, these probably account for less than 5 percent of cases.
Author: John Wegmann, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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