Caution:

This site includes information about child deaths, which some readers may find distressing. If you need support, free and confidential help is available. 

We wish to convey our sincere condolences to the families and friends of the infants, children and young people in NSW who have died. It is our foremost responsibility to learn from these deaths and to use that knowledge to make a difference.

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Sudden Unexpected Death in Infancy (SUDI)

Background

In 2022 and 2023, 66 infants aged under 1 year died suddenly and unexpectedly in NSW - 31 in 2022 and 35 in 2023.

SUDI refers to the sudden and unexpected death of an infant, usually during sleep or in a sleep-related environment, where the cause is not immediately known. 

Each SUDI case in NSW is investigated through police scene examination, medical history review, post-mortem examination, and coronial oversight. SUDI does not include deaths from known illness or visible injury (for example, transport incidents).

SUDI includes both explained and unexplained deaths:

  • Explained SUDI: Investigations identified a cause – for example, infection, undiagnosed conditions, or accidental suffocation in unsafe sleep environments.
  • Unexplained SUDI: A cause of death could not be identified despite full investigation, including cases classified as Sudden Infant Death Syndrome (SIDS).


Findings collected

2009-2023

Page last updated

5 November 2025

Summary from

Biennial report of the deaths of children in NSW 2022 and 2023

2-year period (2022-2023)

Causes of death

Coronial investigations were finalised for 44 of the 66 SUDI deaths in 2022-2023. A cause of death was identified for 9 infants: 

  • Natural causes (6): congenital or chromosomal (1), perinatal (1), infectious or parasitic (2), and endocrine or metabolic conditions (2) 
  • Digestive condition (1) 
  • Accidental threats to breathing (2): accidental suffocation and strangulation in bed 

Risks

Among the 66 SUDI deaths in 2022–2023: 

  • 97% involved at least 1 modifiable factor, such as an unsafe sleep environment or co-sleeping. 
  • 69% involved at least 1 underlying infant factor, including preterm birth, small for gestational age, or low birthweight. 
  • 51% were male. 
  • 83% occurred on bedding not designed for infants. 
  • 68% involved sharing a sleep surface, either intentionally or unintentionally. 

Factors

Research has identified certain factors associated with SUDI. We have consistently reported on multiple risk factors observed when infants die suddenly and unexpectedly, some of which are avoidable. This includes maternal, infant, environmental and socio-demographic factors and the over-representation of vulnerable families.

  • Male children 
  • Aged under 3 months 
  • Low birthweight (<2500g) 
  • Preterm birth (<37 weeks’ gestation) 
  • Small for gestational age <10th percentile (IUGR)
  • Neonatal health problems at birth 
  • Recent illness within 2 weeks of death 

  • Sleeping prone (on the stomach) or on the side 
  • Unsafe sleep surfaces, such as couches or shared surfaces  
  • Co-sleeping in hazardous situations, especially with adults affected by alcohol, drugs, sedating medication or who are smokers 
  • Co-sleeping with an infant aged under 4 months, born preterm and born low birth weight 
  • Loose bedding, pillows  
  • Head covering and excess thermal insulation 
  • Sleeping in a separate room from the caregiver during the early months 
  • Overheating from excess clothing or blankets 

  • Smoking during pregnancy or after birth 
  • Alcohol or substance use during or after pregnancy 
  • Young maternal age or limited access to perinatal care 
  • Not breastfeeding 
  • Social and economic disadvantage 

15-year period (2009-2023)

SUDI deaths, infants <1 year

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Causes of death

Across 2009–2023, of the 655 deaths classified as SUDI, a cause of death was determined for 192 cases: 

  • Natural causes (115 – 60% of explained SUDI): diseases of the respiratory system (35), congenital anomalies (27) and other conditions (53). 
  • External causes (77 – 40%): mostly accidental threats to breathing (62) in unsafe sleeping environments. 

Most infant deaths classified as SUDI in NSW remain unexplained despite investigation, including post-mortem examination. 

Observations

We have consistently observed that certain groups are over-represented in SUDI, including Aboriginal and Torres Strait Islander infants, infants from the most disadvantaged areas and infants with a child protection history.

 

Steps toward prevention

Methamphetamine detection in infant death

We have reviewed the evidence about the risks of methamphetamine exposure in utero and parental methamphetamine use for infants. Since 2019, there has been an increase in the number of infant deaths where methamphetamine was detected at autopsy. Our discussion considers the circumstances of 12 infants who died in the 10-year period 2014-2023, research in other jurisdictions, public inquiries and publicly available health information. We identify the need for further research in this area.

Read our detailed discussion in Chapter 11 of our Biennial Report 2022-2023

Recommendations

NSW Health should develop and implement strategies to promote safe infant sleep practices to vulnerable families. In particular, NSW Health should target:

  • In consultation with the Department of Family and Community Services, families known to child protection services
  • Families living in remote areas of the state, and
  • Families living in areas of greatest socio-economic disadvantage.

That NSW Health complete a detailed audit of compliance with the revised SUDI medical history protocol. The audit should include information and analysis about:

  • The number of infants presented to emergency departments following their sudden and unexpected death.
  • The number of medical history interviews conducted in response to these deaths.
  • An assessment of whether the intent of the Policy Directive has been met and is reflected in the information gathered.
  • Information about the position of the health professional who completed the interviews, the location of the health facility, and the timing of the interview in relation to the death incident.
  • Whether the information gathered in the interview was provided to Forensic Medicine, and the timeliness of this (within 24 hours of the infant’s death).
  • Where SUDI medical history interviews are not conducted, whether relevant staff are aware of Health’s policy, and reasons why the interview was not completed.
  • Details about any strategies or outcomes arising from the audit. 

NSW Health should provide an audit plan and timeframes to the CDRT by 17 December 2021.

NSW Health should review its Management of Sudden Unexpected Death in Infancy Policy Directive, having regard to the results of its audit of compliance with the revised SUDI medical history protocol completed in October 2023. As part of this review, NSW Health should consult with relevant stakeholders referred to in the Policy and the CDRT.


Infant safe sleeping initiatives

We support initiatives that highlight the importance of infant-safe bedding and clear, consistent advice on safe sleeping.

The ACCC has made infant sleep products a safety priority for 2024–2025 and introduced mandatory standards in July 2024 for all infant sleep products. Compliance is required by 19 January 2026.

Red Nose Australia provides information to parents and caregivers on infant safe sleeping and offers bereavement services to support families that have experienced the loss of a child including programs tailored for Indigenous communities.

Monitoring the number and rate of unexplained deaths

We have been monitoring the rate of explained and unexplained deaths since 2010 to identify any trends in the context of SUDI investigations including the completion of a full post-mortem examination.

In 2023, we noted an increase in the number of cases where a full post-mortem examination was not completed, down from 91% in 2018-2019 to 81% in 2020-2021. In 2022-2023, 79% of cases had a full post-mortem examination.

Identifying a cause of death is crucial to preventing SUDI. We are monitoring the number of unexplained deaths in the context of NSW Health's review of the SUDI policy.

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