Data and Statistics

Fast Facts

Each year, there are about 3,400 sudden unexpected infant deaths (SUID) in the United States. These deaths occur among infants less than 1 year old and have no immediately obvious cause.

The three commonly reported types of SUID include the following:

  • Sudden infant death syndrome (SIDS).
  • Unknown cause.
  • Accidental suffocation and strangulation in bed.

In 2020, there were about 1,389 deaths due to SIDS, about 1,062 deaths due to unknown causes, and about 905 deaths due to accidental suffocation and strangulation in bed.

Breakdown of Sudden Unexpected Infant Deaths by Cause, 2020
data table
Percentage
Sudden infant death syndrome 41%
Unknown cause 32%
Accidental suffocation and strangulation in bed 27%

SOURCE: CDC/NCHS, National Vital Statistics System, Mortality Files. Rates calculated via CDC WONDER.

This chart shows the breakdown of sudden unexpected infant deaths (SUID) by cause in 2020.

*SUID cases were reported as shown below:

  • Sudden infant death syndrome (41%)
  • Unknown cause (32%)
  • Accidental suffocation and strangulation in bed (27%)

*Exact values are as follows:

  • Sudden infant death syndrome: 1389
  • Unknown: 1062
  • Accidental suffocation and strangulation in bed: 905
Trends in Sudden Unexpected Infant Death by Cause, 1990–2020
SOURCE: CDC/NCHS, National Vital Statistics System, Mortality Files. Rates calculated via CDC WONDER.
  • This graph shows the trends in sudden unexpected infant death (SUID) rates in the United States from 1990 through 2020.
  • The SUID rate, which includes sudden infant death syndrome (SIDS), unknown cause, and accidental suffocation and strangulation in bed (ASSB), declined considerably beginning in 1990. This decline followed the release of
  • Since 1999, declines have slowed. In 2020, the SUID rate was 92.9 deaths per 100,000 live births.
  • In recent years, SUID is being classified less often as SIDS, and more often as ASSB or unknown cause.
  • SIDS rates declined considerably from 130.3 deaths per 100,000 live births in 1990 to 38.4 deaths per 100,000 live births in 2020.
  • Unknown cause infant mortality rates remained unchanged from 1990 until 1998, when rates began to increase. In 2020, the unknown cause mortality rate in infants was 29.4 deaths per 100,000 live births.
  • ASSB mortality rates remained unchanged until the late 1990s. Rates started to increase beginning in 1997. In 2020, the rate was 25.0 deaths per 100,000 live births.

Codes for cause of death were defined according to the International Classification of Diseases, Ninth Revision (ICD-9) for 1984–1998, and the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10) for 1999–2020. We defined cause of death by using the following underlying cause of death ICD-9 and ICD-10 codes: ASSB (E913.0; W75), SIDS (798.0; R95), and unknown cause, (799.9; R99). The SUID rate was the combination of ASSB, SIDS, and unknown cause deaths.

SUID Rates by State, 2016–2020

SOURCE: CDC/NCHS, National Vital Statistics System, Mortality Files. Rates calculated via CDC WONDER.

This map shows how sudden unexpected infant death (SUID) rates varied by state from 2016 through 2020 among the 50 states and the District of Columbia.

  • Vermont, Massachusetts, California, New Hampshire, and Minnesota had the lowest SUID rates.
  • Mississippi, Alabama, Arkansas, Louisiana, and West Virginia, had the highest SUID rates.
  • The SUID rate in Mississippi (188.2 per 100,000 live births) was almost 4 times the SUID rate in Massachusetts (47.6 per 100,000 live births).
  • There are 27 states with rates above the US average from 2016-2020 (91.7 per 100,000 live births).

There were 20 or fewer deaths in Vermont. As a result, the ranking may be unreliable due to instability in death rates.

Sudden Unexpected Infant Death by Race/Ethnicity, 2015–2019

SOURCE: CDC/NCHS, National Vital Statistics System, Period Linked Birth/Infant Death Data. Rates calculated via CDC WONDER using latest available data by subpopulation (2019).

This stacked bar chart shows sudden unexpected infant death (SUID) rates by cause and by race/ethnicity in the United States from 2015 through 2019. Causes include sudden infant death syndrome (SIDS), unknown cause, and accidental suffocation and strangulation in bed (ASSB).

  • SUID rates per 100,000 live births were highest among non-Hispanic American Indian/Alaska Native (216.0), non-Hispanic Black infants (191.2), and non-Hispanic Native Hawaiian/Other Pacific Islander infants (181.4). SUID rates per 100,000 live births were lowest among non-Hispanic White infants (84.2), Hispanic (55.1) infants, and non-Hispanic Asian infants (22.4).
  • Deaths due to SIDS accounted for the largest proportion of SUID for, non-Hispanic Black infants (39%), non-Hispanic Native Hawaiian/Other Pacific Islander infants (48%), and non-Hispanic White infants (41%).
  • Deaths due to unknown causes accounted for the largest proportion of SUID for non-Hispanic American Indian/Alaska Native (40%), Hispanic infants (42%) and non-Hispanic Asian infants (39%).
  • ASSB accounted for the smallest proportion of SUID for most racial groups, ranging from 21% of SUID among Hispanic infants to 27% of SUID among non-Hispanic Native Hawaiian/Other Pacific Islander and non-Hispanic White infants.

All records that indicted Hispanic ethnicity are classified as Hispanic regardless of race. For brevity, text references omit the term “single-race.”

When the number of deaths is small (20 or less), rankings may be unreliable due to instability in death rates. The death rates for NH NHOPI for unknown cause or accidental suffocation and strangulation in bed are fewer than 20.

Data Resources for SUID and SIDS

Downloadable public-use data files for independent research and analyses as well as annual mortality reports, are available from the National Center for Health Statistics.

Available datasets include

  • Birth data files.
  • Period linked birth-infant death data files.
  • Birth cohort linked birth-infant death data files.
  • Mortality multiple cause data files.
  • Fetal death data files.

Pregnancy Risk Assessment Monitoring System (PRAMS) Data
PRAMS may be used to access the latest data on maternal and child health indicators, including infant sleep practices.

Data Access Tools

The following data analyses tools allow users to access and examine vital statistics and other population data interactively are available online:

CDC Wonder (Wide-ranging Online Data for Epidemiologic Research)
Allows users to query CDC data sources, including National Center for Health Statistics birth and death data using a menu-driven system.

WISQARS (Web-based Injury Statistics Query and Reporting System)
Allows users to access and examine injury-related data to generate customized reports.