Facts About SUDC

  • Sudden Unexplained Death in Childhood (SUDC) is the sudden and unexpected death of a child, between 1 and 18 years of age, which remains unexplained after a thorough case investigation is conducted. This must include; examination of the death scene, performance of a complete post-mortem, and a review of the child and family’s medical history (Medically defined by Krous et al in 2005). 
  • SUDC is a category of death that eludes our scientific understanding today.
  • We do not currently know of any way to reduce the risk of Sudden Unexplained Death in Childhood.
  • At this time, no-one can predict or prevent these deaths; neither parents nor medical professionals.

40 children

ONS data indicates:

  • Approximately 40 children in the UK are affected by SUDC each year.
  • Sudden Unexplained Death In Childhood is the 4th leading category of death for children aged 1-4 years.
  • There are more young unexplained childhood deaths (at 1-9 years of age) than deaths due to traffic accidents, fires or drowning. 

Statistics in the UK

Variation in investigation and certification mean we do not know exactly how often SUDC occurs. The lack of a single, specific code for the sudden and unexplained death of a child, and limited awareness, means a range of terms are used in these cases. For more information on terminology please visit our webpage on the child death process.

Currently the best way to annually estimate the incidence of SUDC, is to examine a range of data for  ‘ill-defined and unknown causes of mortality’- World Health Organisation ICD-10 codes R95-99. 

Click chart to expand

This chart displays the number of unexplained child deaths since 2011 years in England and Wales reported by the Office of National Statistics (ONS). The data is visually separated out by year and columns divided by age. Due to inconsistencies in certification, it is not advisable to draw conclusions about a change in the incidence of SUDC over time. However, it shows the numbers are variable with a range of 27-55 cases reported in a single year; comparable to 1-2 children dying every fortnight. The average number of deaths in one year over this time period is 41.

Sudden Unexplained Death in Childhood can affect children of any age from 1-18. However, it appears to be most prevalent in toddlers and children in their late teens. This distribution of deaths is consistent with international data.

Most recent ONS data:  2022

41 child deaths were reported as ICD-10 codes R96-R99 in England and Wales in 2022:

  • 25 one-four year olds
  • 5 five-nine year olds
  • 3 ten-fourteen year olds
  • 8 fifteen-nineteen year olds

Additional data sources report:

  • 8 children were affected in Scotland (National Records of Scotland)
  • No children were affected in Northern Ireland in 2021 (Northern Ireland Statistics and Research agency – 2022 data not yet available)

Further information

  • In England and Wales in 2022 there were 380 deaths of children aged 1-4 years and 6.5% of these were sudden and unexplained.
  • SUDC is rare, with a crude death rate of 0.93 per 100,000 in the UK for the age range most commonly affected (children aged 1-4 years) in England and Wales 2022.
  • Since 2020, SUDC is the 4th leading cause of death in the UK for children age 1-4 years, following the leading categories: cancer, congenital malformations and accidents. SUDC is the 10th leading cause of death across the broader child age range of ONS data 1-19 yrs.
  • Some deaths without a clear and evidenced explanation may be categorised as explained or other ‘explained, unspecified’ ICD codes. Hence, these figures may be an underrepresentation.
  • Sudden Unexplained Death in Childhood is not restricted to the UK and more information from the WHO and CDC database is available from the SUDC Foundation website.

Profile of a child affected by SUDC

Published epidemiological data suggests the following profile for a child affected by SUDC:

    • Most often between 1 and 2 years of age
    • Most often the child is male
    • Died an unwitnessed death during apparent sleep
    • In nearly all cases children are found prone (sleeping on their front)
    • Approximately half have an illness or terminal fever which cannot explain the death
    • The child’s development is usually within normal limits and vaccinations are up to date
    • There is also published evidence to suggest an association between febrile seizures and SUDC with a higher proportion of families reporting a history of febrile seizures than is known to occur in the general population (For example, 28.8% vs 2-5% reported in Crandall et al, 2019). This association was corroborated in the NCMD population data report in December 2022.


  • Gould L, Delavale V, Plovnick C, Wisniewski T, Devinsky O. Are brief febrile seizures benign? A systematic review and narrative synthesis. Epilepsia. 2023 Oct;64(10):2539-2549. doi: 10.1111/epi.17720. Epub 2023 Aug 7. PMID: 37466925.
  • Crandall et alLG, Lee JH, Stainman R, Friedman D, Devinsky O. Potential Role of Febrile Seizures and Other Risk Factors Associated With Sudden Deaths in Children. JAMA Netw Open. 2019 
  • Hefti MM, Kinney HC, Cryan JB, Haas EA, Chadwick AE, Crandall LA, Trachtenberg FL, Armstrong DD, Grafe M, Krous HF. Sudden unexpected death in early childhood: general observations in a series of 151 cases: Part 1 of the investigations of the San Diego SUDC Research Project. Forensic Sci Med Pathol. 2016 
  • Hesdorffer DC, Crandall LA, Friedman D, Devinsky O. Sudden unexplained death in childhood: A comparison of cases with and without a febrile seizure history. Epilepsia. 2015 
  • McGarvey CM, O’Regan M, Cryan J, Treacy A, Hamilton K, Devaney D, Matthews T. Sudden unexplained death in childhood (1-4 years) in Ireland: an epidemiological profile and comparison with SIDS. Arch Dis Child. 2012

For more detailed information, please see published research on SUDC or contact us.

Hope for the future

The advocacy work of SUDC UK, research projects and the National Child Mortality Database (NCMD) in England will hopefully provide more accurate information on this category of death. We hope this will help encourage appropriate urgency for investigating, understanding and preventing SUDC. 

NCMD published a thematic review of SUDC in 2022. This showed that 30% of child deaths in the UK are sudden and unexpected and 19% were sudden, unexplained and lacked an immediately apparent reason of the death. After the investigation and post mortem examination, 16% still had no explanation. This report included deaths of infants and children 0-18 years and highlighted an association between seizures and SUDC.

In 2023, SUDC UK collaborated with NCMD to update the Child Death Review data collection forms including the supplementary form for SUDC and a checklist to help investigation. Additional fields were added including more detail on medical history (including febrile seizures, cardiac conditions and allergies). SUDC UK also supported the launch of genetic testing for SUDC in 2023. We hope that this information will encourage improved care and conversations with parents and help inform research in the future to better understand SUDC and prevent deaths.

Toddler in dungarees smiling at camera