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Report advises pediatricians to be cognizant of terminology surrounding SIDS

September 20, 2021

The lack of consistency and consensus on what terminology to use when an infant dies suddenly and unexpectedly has created confusion among pediatricians, medical examiners/coroners, public health officials and families.

To address this, a new AAP clinical report calls for cohesive, coherent and consistent terminology to help parents and caregivers heal, identify epidemiologic trends and reduce the risk of these deaths.

The report Half Century Since SIDS: A Reappraisal of Terminology describes the history of sudden infant death syndrome (SIDS) terminology and summarizes the decades-long debate and resulting diagnostic shift. It also recommends system changes and urges pediatricians to be cognizant of the terminology they use with families.

The report from the AAP Task Force on Sudden Infant Death Syndrome; Council on Child Abuse and Neglect; Council on Injury, Violence and Poison Prevention; Section on Child Death Review and Prevention; and the National Association of Medical Examiners is available at and will be published in the October issue of Pediatrics.

What should these deaths be called?

Bruce Beckwith, M.D., defined SIDS in 1969 as “the sudden death of any infant or young child, which is unexpected by history, and in which a thorough post-mortem examination fails to demonstrate an adequate cause for death.” Sudden refers to the fact that death comes without warning, and unexpected means there was no known preexisting condition that could have reasonably predicted it.

This definition established a common term that focused attention on this group of infant deaths and helped address the stigma associated with these deaths. The term SIDS and its definition subsequently were adopted internationally, allowing researchers and policymakers to establish a scientific research agenda to explore its epidemiology and etiology.

Variety of acronyms

Since then, U.S. death certifiers (medical examiners and coroners) have used a variety of terms, including undetermined, unexplained and unknown cause, as well as SIDS, sudden unexplained (or unexpected) infant death (SUID or SUDI), and accidental suffocation or asphyxia in an unsafe sleeping environment.

SUID has become an umbrella term to describe sudden infant deaths, including those deaths previously called SIDS. The “U” in SUID can refer either to unexpected or unexplained.

Because these deaths commonly occur in an unsafe sleeping environment, they increasingly are referred to as sleep-related infant deaths. The AAP has acknowledged terms other than SIDS, including SUID and sleep-related infant deaths in the clinical reports SIDS and Other Sleep-Related Infant Deaths: Updated 2016 Recommendations for a Safe Infant Sleeping Environment and Identifying Child Abuse Fatalities During Infancy.

Debate, disagreement

Even with periodic revisions to the 1969 SIDS definition, vigorous debate continues regarding the labeling and classification of sudden unexplained infant deaths. Many academic and clinical researchers favor SIDS because it was the term used most often in etiologic and observational risk factor studies published in the 1970s-’90s.

Some of the controversy around SIDS stems from disagreement as to whether infant deaths meeting the SIDS definitions constitute a “syndrome” — a term that refers to a disease or condition with a common group of signs and symptoms. Others argue that the term SIDS conveys a certainty of diagnosis, although the underlying cause of SIDS remains unknown.

Steps for the pediatrician

Pediatricians are trusted sources of information for families and communities, and facilitate the adoption of safe sleep practices and other strategies to reduce the risk of infant sleep-related deaths. Therefore, it is important for pediatricians to understand the changes in terminology surrounding SIDS/SUID.

In addition, pediatricians often are the first health care professionals to speak with grieving parents about possible causes of infant death and support families through counseling and the assessment of surviving siblings for potential shared congenital or genetic conditions.

When communicating with families after an infant death, pediatricians should avoid blaming the family or inciting feelings of guilt. Yet, they should acknowledge potentially unsafe behaviors or hazards in the environment and talk with families about how risks in the prenatal period or unsafe sleep practices may pose a risk to surviving or subsequent children.


The clinical report includes the following recommendations:

  • Terminology proposed by the National Association of Medical Examiners Panel on Sudden Unexpected Death in Pediatrics (which included AAP members) should be adopted. Death certifiers and child protective service agencies should use “unexplained sudden death” rather than SIDS.
  • Medical examiners should have a formal mechanism to report their findings to the primary care pediatrician or other clinicians, who then could offer the family a chance to review the findings, discuss possible contributing factors and receive referrals for specialist or mental health care.
  • All professionals should be trained in effective communication practices that prioritize empathy and sensitivity in sudden infant death and all fatality investigations.

Dr. Palusci is a co-author of the clinical report and is a member of the Section on Child Death Review and Prevention Executive Committee. Dr. Hoffman is a co-author of the report and chairs the Council on Injury, Violence and Poison Prevention.

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