Among 4,861 sudden unexpected infant deaths (SUIDs) in the CDC case registry from 2020-2024, unsafe sleep factors were present in at least three fourths of cases, with most decedents being aged 0-3 months, male, Black or African American or White, and insured by Medicaid.
Key Findings
Background
Sudden unexpected infant death (SUID) accounts for approximately 3,400 deaths among infants aged less than 1 year in the United States annually.
SUID vital statistics data do not include details on sleep environment and other contextual factors critical for surveillance and prevention.
CDC's SUID and Sudden Death in the Young Case Registry is a multijurisdictional, population-based active surveillance system that compiles detailed information from multiple data sources.
The case registry builds on child death review programs and covers deaths in persons aged 0-18 years.
Methods
The analysis included 4,861 SUIDs from the CDC case registry covering 2020-2024.
The case registry is a multijurisdictional, population-based active surveillance system.
Data were drawn from multiple data sources compiled through child death review programs.
The analysis described SUID by sociodemographic characteristics, sleep environment characteristics, case registry classification algorithm categories, and death investigation components.
Results
Most SUID decedents were aged 0-3 months, male, Black or African American or White, born full-term, and insured by Medicaid.
Age group 0-3 months represented the majority of decedents.
Male sex predominated among SUID cases.
Racial composition was primarily Black or African American or White.
Most decedents were born full-term.
Medicaid was the predominant insurance type among decedents.
Results
Unsafe sleep factors were present in at least three fourths of SUID cases.
The American Academy of Pediatrics recommends infants be placed to sleep supine on a flat, firm, nonshared surface, without soft bedding.
Unsafe sleep factors were identified in at least 75% of the 4,861 SUIDs analyzed.
Sleep environment details are not captured in standard vital statistics data, making the case registry critical for understanding these factors.
Results
Almost all infants had an autopsy and death investigation, although completed components of investigations varied.
Near-universal autopsy and death investigation rates were documented across the 4,861 SUIDs.
The specific components completed during death investigations varied across cases.
Variability in investigation components has implications for the completeness and quality of SUID surveillance data.
Results
The case registry classification algorithm was used to categorize SUID into subcategories.
The case registry applies a classification algorithm to assign SUID categories to each death.
This categorization helps distinguish among different etiologies and circumstances of sudden unexpected infant death.
Detailed classification supports targeted prevention efforts beyond what standard vital statistics allow.
Conclusions
Detailed case registry data can be used to improve death investigations, increase understanding of etiologies and risk factors, and enhance focused prevention efforts.
The data are intended for use by public health professionals and clinicians.
The case registry fills a gap left by vital statistics data, which lack contextual and sleep environment details.
Authors highlight the potential of this information to support SUID prevention efforts.
What This Means
This research examined detailed records of 4,861 sudden unexpected infant deaths (SUIDs) — which include sudden infant death syndrome (SIDS) and other unexplained infant deaths — reported to the CDC's national case registry between 2020 and 2024. Each year, about 3,400 infants under age 1 die from SUID in the United States. The study found that most of these infants were between 0 and 3 months old, male, Black or African American or White, born at full term, and covered by Medicaid. Critically, unsafe sleep conditions — such as being placed to sleep on a shared surface, on soft bedding, or in a non-supine position — were present in at least three out of four of these deaths.
This research suggests that unsafe sleep environments remain a major and persistent factor in infant deaths, even though guidelines recommending safe sleep practices have existed for decades. The findings also highlight that while nearly all of these deaths received an autopsy and formal investigation, the thoroughness of those investigations varied considerably, which can make it harder to understand the true causes and risk factors involved.
The practical importance of this work is that standard death records — like death certificates — do not capture details about where and how an infant was sleeping at the time of death. This specialized registry fills that gap, giving public health officials and pediatric clinicians much richer information to design better prevention programs, improve how deaths are investigated, and target outreach to communities and families at higher risk.
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Lambert A, Parks S, Cottengim C, Mohamoud Y, Ly K, Kroelinger C, et al.. (2026). Characteristics of Sudden Unexpected Infant Deaths - United States, 2020-2024.. MMWR. Morbidity and mortality weekly report. https://doi.org/10.15585/mmwr.mm7535a1