Sudden Infant Death Syndrome - ACPN

Sudden Infant Death Syndrome

Sudden Infant Death Syndrome (SIDS) or crib death is a syndrome marked by the sudden death of an infant that is unexpected by history and remains unexplained after a thorough forensic autopsy and a detailed death scene investigation.


Typically the infant is found dead after having been put to bed, and exhibits no signs of having suffered.

SIDS is a diagnosis of exclusion. It should only be applied to an infant whose death is sudden and unexpected and remains unexplained after the performance of an adequatepostmortem investigation including:

  • an autopsy;
  • investigation of the scene and circumstances of the death;
  • Exploration of the medical history of the infant and family.

Australia and New Zealand are shifting to the term Sudden Unexplained Death in Infancy (SUDI) for professional, scientific and coronial clarity.

The term SUDI is now often used instead of Sudden Infant Death Syndrome (SIDS) because some coroners prefer to use the term ‘undetermined’ for a death previously considered to be SIDS. This change is causing diagnostic shift in the mortality data.

Risk Factors

be a strong function of the infant’s sex, age and ethnicity, and the education and socio-economic-status of the infant’s parents.

According to a study published on November 1, 2006 in the Journal of the American Medical Association, babies who die of SIDS have abnormalities in the brain stem (themedulla oblongata), which helps control functions like breathing, blood pressure and arousal, and abnormalities in serotonin signaling. According to the National Institutes of Health, which funded the study, this finding is the strongest evidence to date those structural differences in a specific part of the brain may contribute to the risk of SIDS.

In a British study released May 29, 2008 researchers discovered that the common bacterial infections Staphylococcus aureus (staph) and Escherichia coli (E. coli) appear to be a risk factor in some cases of SIDS. Both bacteria were present at greater than usual concentrations in infants who died from SIDS.[4] SIDS cases peak between eight and ten weeks after birth, which is also the time frame in which the antibodies that were passed along from mother to child are starting to disappear and babies have not yet made their own antibodies.

Listed below are several risk factors associated with increased probability of the syndrome based on information available prior to this recent study.

Prenatal Risks

  • maternal nicotine use (tobacco or nicotine patch)[5]
  • inadequate prenatal care[6]
  • inadequate prenatal nutrition[7]
  • use of heroin, cocaine and other drugs[8]
  • subsequent births less than one year apart[9]
  • alcohol use[10]
  • infant being overweight
  • mother being overweight
  • Teen pregnancy (if the baby has a teen mother, it has a greater risk) infant’s sex (60% of SIDS cases occur in males)

Post-Natal Risks

  • Mold (can cause bleeding lungs plus a variety of other uncommon conditions leading to a misdiagnosis and death). It is often misdiagnosed as a virus, flu, and/or asthma-like conditions.
  • low birth weight (in the U.S. from 1995-1998 the rate for 1000-1499 g was 2.89/1000 and for 3500-3999 g it was 0.51/1000)
  • exposure to tobacco smoke
  • prone sleep position (lying on the stomach, see sleep positioning below)
  • not breastfeeding
  • elevated or reduced room temperature
  • excess bedding, clothing, soft sleep surface and stuffed animals
  • co-sleeping with parents or other siblings may increase risk for SIDS, but the mechanism remains unclear
  • infant’s age (incidence rises from zero at birth, is highest from two to four months, and declines towards zero at one year)
  • Premature birth (increases risk of SIDS death by about 4 times.
  • In 1995-1998 the U.S. SIDS rate for 37–39 weeks of gestation was 0.73/1000; The SIDS rate for 28–31 weeks of gestation was 2.39/1000)