SIDS Statistics (2023)

Healthy newborn baby sleeping on white sheet.

SIDS Stats at a Glance

  • 1386 infants in the US died from SIDS in 2020 (the most recent year data is available).
  • SIDS is the second-leading cause of infant death in the US, behind extreme immaturity (2380 deaths in 2020).
  • Most SIDS cases occur between two and four months old.
  • Boys make up 61% of SIDS fatalities.
  • SIDS rates have declined over the past few decades, from 130.27 deaths per 100,000 live births in 1990 to 38.4 in 2020.
  • This decline is widely attributed to the release of The American Academy of Pediatrics’ safe sleep recommendations in 1992, the launch of the Safe to Sleep (formerly Back to Sleep) campaign in 1994, and the reclassification of some SIDS cases to other causes.
  • US infants also died from SIDS-related causes known as sudden unexpected infant deaths (SUID), which include unknown causes (1051 deaths) and accidental suffocation and strangulation in bed, or ASSB (905 deaths).
  • 3356 infants in the US died in 2020 from all SUID-related causes, with SIDS being the leading cause of SUID.
  • Massachusetts and Vermont had the lowest SUID rates in 2020 (47.6 deaths per 100,000 live births each), while Mississippi had the highest (188.2 deaths per 100,000 live births). 
  • Pacific Islanders are the US racial group experiencing the highest rate of SIDS (87.2 deaths per 100,000 live births), while Asians are the lowest (7.7 deaths per 100,000 live births).

What is SIDS?

SIDS (Sudden Infant Death Syndrome) is the sudden and unexplained death of a seemingly healthy baby under 12 months of age. 

Such deaths are often classified as SIDS if the cause of death cannot be identified after a full investigation.

SIDS deaths have been declining in recent decades, with a sharp drop in the 90s credited to the Safe to Sleep campaign and a much slower decline since then. In 2020 the US saw a slight uptick in SIDS.

What is SUID?

SIDS is a subset of the larger group of SUID (Sudden Unexplained Infant Death) deaths. SUID can include unknown causes, as well as accidental suffocation and strangulation in bed, or ASSB. SIDS is the leading cause of SUID.

About 3400 babies in the US die of SUID each year, with about 1400 of those deaths caused by SIDS.

Sources: MedScape, CDC

What Causes SIDS?

The cause of SIDS is unknown but is thought to include both physical and environmental factors. 

Physical Factors

  • Brain: SIDS may be associated with a brain defect impacting infant breathing and waking from sleep.
  • Respiratory: Infections affecting breathing, such as colds, could increase the likelihood of SIDS.
  • Premature birth: Low birth weight or a brain that hasn’t had time to fully develop may be a contributing factor to SIDS.

Environmental Factors

  • Stomach or side sleeping: Babies sleeping on their backs appear to have a lower risk of SIDS, while those sleeping on their stomachs or sides may have more trouble breathing.
  • Bed sharing or co-sleeping: While babies who sleep in the same room as their parents have a lower risk of SIDS, they should not share the same bed with their parents or other children. Instead, they should sleep in their own crib or bassinet. 
  • Soft surface sleeping: Soft mattresses, pillows, waterbeds, or fluffy comforters may interfere with an infant’s breathing and increase the risk of SIDS.
  • Secondhand smoke: Babies exposed to smoking, either in the womb or after birth, appear to have a significantly increased risk of SIDS.
  • Overheating: If a baby is too warm it can lead to hyperthermia and increase their risk of SIDS.

Sources: Mayo Clinic, NIH

ASSB Risk Factors

Other factors can lead to infant accidental suffocation and strangulation in bed, or ASSB. Note, however, that such cases are not considered SIDS since they have an identifiable cause.

  • Gaps in mattresses: If a mattress is not well-fitted a baby may become entrapped in the gap between the edge of the mattress and some other surface, such as a wall or the edge of a crib.
  • Cluttered sleeping areas: Excessive blankets, stuffed animals, or other objects or materials in the infant’s sleeping area can potentially lead to suffocation or strangulation.

What Are Known Risk Factors for SIDS?

Several factors are believed to contribute to the risk of SIDS.

  • Age: Most SIDS cases occur between two and four months old.
  • Sex: Boys comprise 61% of SIDS cases.
  • Genetics: Siblings of children who died of SIDS are four times more likely to die of SIDS.
  • Race: Asian, Hispanic, and White infants are less likely to die from SIDS, while Pacific Islander, Black, and Native American infants have a greater risk.

Maternal Risk Factors

Maternal risk factors include the following:

  • Mother under the age of 20
  • Smoker
  • Uses drugs or alcohol
  • Inadequate prenatal care

Sources: CDC, Mayo Clinic, JAMA Open Journal

SIDS Distribution by State

SIDS rates are lowest in Massachusetts, Vermont, California, New Hampshire, and Minnesota. SIDS rates are highest in Mississippi, Alabama, Arkansas, Louisiana, and West Virginia.

Sources: CDC

How Can SIDS Be Prevented?

The best way to prevent SIDS is to avoid as many of the risk factors mentioned above as possible. To minimize the risk of SIDS, a baby should:

  • Be placed on their back to sleep.
  • Sleep in their parent’s room (but not in their parent’s bed).
  • Have their own dedicated sleep space designed for them. 
  • Use a firm, flat, level mattress covered only with a fitted sheet.
  • Have all objects removed from the sleeping area. 

Sources: NIH

The information WonderBaby provides is not intended to be, and does not constitute, medical or other health advice or diagnosis and should not be used as such. Always consult with a qualified medical professional about your specific circumstances.