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Sudden infant death syndrome and sleep-related infant death

Sometimes a baby younger than one year dies suddenly and unexpectedly. When a full investigation finds no cause, the death is called sudden infant death syndrome (SIDS). Safe sleep steps can lower the risk. Sleep itself does not cause SIDS.

  • Condition
  • In this atlas

Overview

Technical summary

NICHD defines SIDS as the sudden death of a baby younger than 1 year that has no known cause even after a full investigation (complete autopsy, examination of the death scene and review of the clinical history). Sudden unexpected infant death (SUID) is the umbrella category for all sudden, unexpected infant deaths, whether from a known cause such as an injury or accident or an unknown cause such as SIDS. About 3,000 SUIDs occur in the United States each year, and more than 1 in 3 are SIDS (see the claim on this page). MedlinePlus says the cause of SIDS is unknown, that it is the leading cause of death between one month and one year, and lists steps to reduce risk. MedlinePlus and NICHD both list feeding human milk among the steps that lower the risk. The recipient is the infant.

Assessment

NICHD says a death is categorised as SIDS by a medical examiner or coroner when the investigation cannot determine a cause or explain why the baby died.

Burden

  • Burden Observational Certainty not assessed

    NICHD describes sudden infant death syndrome (SIDS) as the sudden death of a baby younger than 1 year of age that does not have a known cause, even after a full investigation. Sudden unexpected infant death (SUID) is the wider group: all sudden, unexpected infant deaths, whether from a known cause such as an injury or accident or from an unknown cause such as SIDS. About 3,000 SUIDs occur in the United States every year, and more than 1 in 3 of them are from SIDS.

    Applies to Child
    • Babies younger than 1 year of age and the people who care for them. The Safe to Sleep campaign addresses parents, grandparents, other relatives, babysitters, child care providers and anyone who might care for a baby. Counts on the page are for the United States.
    • Home and child care sleep settings (the page lists parents, babysitters and child care providers).
    • United States (NICHD campaign)
    • Newborn and infant, younger than 1 year
    • Gestational age Not reported
    • Postnatal age Not reported
    Follow-up Not applicable (guidance and national counts)
    Certainty method
    Not assessed
    Limitations
    The counts are from a NICHD page that cites a 2024 CDC data page, which the atlas did not read; the page does not say which year the counts refer to, and it gives rounded figures. The page does not give a rate per births. The definition of SIDS depends on an investigation, so a death that is later explained is not counted as SIDS.
    Last checked
    2026-10-14
    Next evidence check due
    Not scheduled
    Sources and citations (6)

    1. Supports What is SIDS? (Safe to Sleep campaign)

      Webpage · Safe to Sleep campaign, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) · Edition The page as shown on 2026-10-14. The page carries no edition date. Its United States counts are cited on the page to a 2024 CDC data page, which the atlas did not read.

      Locator
      What is SIDS?, paragraph 1
      How it applies
      Definition of SIDS, part 1.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f6614c996b312a27d25c11479b0a82c1ed2e89191aa3739fc977a5a9118f8eca
      Reuse basis
      NICHD disclaimer page (fetched as mj-nichd-disclaimer.html, sha256 08010c9291ae905c92c643e1625556614b3f7e6da0a7fd7b20af1781b66b3adf) says most text on the NICHD website is in the public domain and not subject to copyright, and that images and logos are not. The page bytes are not committed. Short quotations with attribution.

    2. Supports What is SIDS? (Safe to Sleep campaign)

      Webpage · Safe to Sleep campaign, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) · Edition The page as shown on 2026-10-14. The page carries no edition date. Its United States counts are cited on the page to a 2024 CDC data page, which the atlas did not read.

      Locator
      Is it always SIDS?, paragraph 3
      How it applies
      Definition of SUID.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f6614c996b312a27d25c11479b0a82c1ed2e89191aa3739fc977a5a9118f8eca
      Reuse basis
      NICHD disclaimer page (fetched as mj-nichd-disclaimer.html, sha256 08010c9291ae905c92c643e1625556614b3f7e6da0a7fd7b20af1781b66b3adf) says most text on the NICHD website is in the public domain and not subject to copyright, and that images and logos are not. The page bytes are not committed. Short quotations with attribution.

    3. Supports What is SIDS? (Safe to Sleep campaign)

      Webpage · Safe to Sleep campaign, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) · Edition The page as shown on 2026-10-14. The page carries no edition date. Its United States counts are cited on the page to a 2024 CDC data page, which the atlas did not read.

      Locator
      How common is SIDS?, sentence 1
      How it applies
      Annual number of SUIDs in the United States.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f6614c996b312a27d25c11479b0a82c1ed2e89191aa3739fc977a5a9118f8eca
      Reuse basis
      NICHD disclaimer page (fetched as mj-nichd-disclaimer.html, sha256 08010c9291ae905c92c643e1625556614b3f7e6da0a7fd7b20af1781b66b3adf) says most text on the NICHD website is in the public domain and not subject to copyright, and that images and logos are not. The page bytes are not committed. Short quotations with attribution.

    4. Supports What is SIDS? (Safe to Sleep campaign)

      Webpage · Safe to Sleep campaign, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) · Edition The page as shown on 2026-10-14. The page carries no edition date. Its United States counts are cited on the page to a 2024 CDC data page, which the atlas did not read.

      Locator
      How common is SIDS?, sentence 2
      How it applies
      Share of SUIDs that are SIDS.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f6614c996b312a27d25c11479b0a82c1ed2e89191aa3739fc977a5a9118f8eca
      Reuse basis
      NICHD disclaimer page (fetched as mj-nichd-disclaimer.html, sha256 08010c9291ae905c92c643e1625556614b3f7e6da0a7fd7b20af1781b66b3adf) says most text on the NICHD website is in the public domain and not subject to copyright, and that images and logos are not. The page bytes are not committed. Short quotations with attribution.

    5. Background What is SIDS? (Safe to Sleep campaign)

      Webpage · Safe to Sleep campaign, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) · Edition The page as shown on 2026-10-14. The page carries no edition date. Its United States counts are cited on the page to a 2024 CDC data page, which the atlas did not read.

      Locator
      Citations
      How it applies
      Source the page cites for the counts.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f6614c996b312a27d25c11479b0a82c1ed2e89191aa3739fc977a5a9118f8eca
      Reuse basis
      NICHD disclaimer page (fetched as mj-nichd-disclaimer.html, sha256 08010c9291ae905c92c643e1625556614b3f7e6da0a7fd7b20af1781b66b3adf) says most text on the NICHD website is in the public domain and not subject to copyright, and that images and logos are not. The page bytes are not committed. Short quotations with attribution.

    6. Background Sudden Infant Death Syndrome (MedlinePlus health topic)

      Webpage · MedlinePlus, National Library of Medicine · Edition The health topic page as shown on 2026-10-14. The page carries no edition date. The summary is credited on the page to NIH: National Institute of Child Health and Human Development.

      Locator
      Summary, paragraph 1
      How it applies
      MedlinePlus definition of SIDS.
      Retrieved
      Source effective date
      Not reported
      Source state
      Current
      Snapshot hash
      f7b1a4baa716d01aa2ebe8877c5a3282f089ac2011ff10af63f40fa2ab43c145
      Reuse basis
      MedlinePlus page Linking to and Using Content (fetched as mj-medlineplus-using-content.html, sha256 31267ce9db016893b80c5665312d92ffc8c34ec86916f84708c353936ba52228) lists summaries on health topic pages as public-domain content. The page bytes are not committed. Short quotations with attribution.

Record details

Record id
maternal:sudden-unexpected-infant-death
Content hash
bf182ff97fb668330ea2e44ca42c93835ebe4b835f792c83fa2296026a5c6fa3