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Sudden Infant Death Syndrome (SIDS)

Toy blocks spelling out SIDSOctober is SIDS Awareness Month. Learn more about infant deaths from SIDS and other causes, and take action to reduce the risk. Start by always placing babies on their backs to sleep.

Understanding the Problem

About 3,500 infants die suddenly and unexpectedly each year in the United States. These deaths are called sudden unexpected infant deaths (SUID). Often, an autopsy alone cannot explain these deaths without investigating the scene and reviewing the infant's medical history.

The most common causes of SUID include the following:

  • Sudden Infant Death Syndrome (SIDS) is the sudden death of an infant less than 1 year old that cannot be explained after a thorough investigation that includes a complete autopsy, examination of the death scene, and a review of the medical history. SIDS is the leading cause of death for infants aged 1 to 12 months. About half of SUIDs are SIDS.
  • Unknown Cause is the sudden death of an infant less than 1 year old that cannot be explained. Often, a thorough investigation was not conducted, and cause of death could not be determined.
  • Accidental Suffocation and Strangulation in Bed (ASSB) is the leading cause of infant death due to injury. Things that can lead to accidental suffocation or strangulation include the following:
    • Suffocation by soft bedding—for example, when a pillow or waterbed mattress covers an infant's nose and mouth.
    • Overlay—for example, when another person rolls on top of or against the infant.
    • Wedging or entrapment—for example, when an infant is wedged between two objects such as a mattress and wall, bed frame, or furniture.
    • Strangulation—for example, when an infant's head and neck get caught between crib railings.

Black and American Indian/Alaska Native infants are about twice as likely to die of SIDS and other sleep-related SUID as white infants.

Safe to Sleep

CDC is working with the National Institutes of Health in its Safe to Sleep campaign, formerly known as the Back to Sleep campaign. The Safe to Sleep campaign has outreach and education activities aimed at reducing infant death from SIDS and other sleep-related causes.

Mother laying baby down in crib

Always place babies on their backs to sleep for every sleep.

Reducing the Risk

Doctors and researchers don't know the exact causes of SIDS. However, research shows that parents and caregivers can take the following actions to help reduce the risk of SIDS and other sleep-related causes of infant death:

  • Always place babies on their backs to sleep for every sleep.
  • Use a firm sleep surface, such as a mattress in a safety-approved crib, covered by a fitted sheet.
  • Have the baby share your room, not your bed. Your baby should not sleep in an adult bed, on a couch, or on a chair alone, with you, or with anyone else.
  • Keep soft objects such as pillows and loose bedding out of your baby's sleep area.
  • Do not smoke during pregnancy or around the baby because these are important risk factors for SIDS. The risk of SIDS is even stronger when a baby shares a bed with a smoker. To reduce risk, do not smoke during pregnancy, and do not smoke or allow smoking around your baby. For help in quitting, call the quitline at 1-800-QUIT-NOW (1-800-784-8669) or visit smokefreewomen.

For more information on reducing the risk of SIDS, see Ways to Reduce the Risk of SIDS and Other Sleep-Related Causes of Infant Death.

Learn more about safe sleep environments and reducing the risk of SIDS and other sleep-related infant deaths by reading What Does a Safe Sleep Environment Look Like? [PDF - 336KB].

In addition, CDC supports the 2011 recommendations issued by the American Academy of Pediatrics (AAP) to reduce the risk of sleep-related infant deaths, including SIDS. Learn more at the Healthy Children website, sponsored by AAP.

Improving Reporting of SIDS and Other Sleep-Related SUID

CDC is committed to tracking and reducing SIDS and other sleep-related SUID. CDC activities include:

The SUID Case Registry
The SUID Case Registry allows states to use the same case definitions, which helps them track SUID trends by getting more complete and accurate data faster. A better understanding of the circumstances and events around SUID may help reduce future deaths.

The Sudden Death in the Young (SDY) Case Registry
The SDY Case registry expands the kinds of cases tracked in the SUID Case Registry from infancy through adolescence. The SDY registry includes an advanced review where cases are discussed and categorized by pediatric clinical specialists, such as cardiologists and neurologists, working with forensic pathologists. A blood sample is also collected at autopsy for future research into the cause of death. For more information, see Frequently Asked Questions about the Sudden Death in the Young Case Registry.

Training Materials
CDC developed the Sudden Unexplained Infant Death Investigation Reporting Form and worked with other organizations and experts to develop training materials for infant death investigators and instructors.