Sudden Infant Death Syndrome and Infant Mortality IDPH Home Page

SIDS Fact Sheet

What is SIDS?

Sudden Infant Death Syndrome (SIDS) is the sudden, unexpected death of an infant under 1 year of age that remains unexplained after a complete investigation, including:

  1. an autopsy;
  2. examination of death scene; and
  3. review of medical history.

In the United States, SIDS is the major cause of death in infants between 1 month and 1 year of age, with most deaths occurring between 2 and 4 months. SIDS happens in families of all social, economic and ethnic groups. SIDS is not contagious, predictable or preventable. SIDS is sudden and silent, occurring most often during sleep, with no signs of suffering. Terms used in the past to describe SIDS include “crib death” or “cot death.”

How Common is SIDS?

The SIDS rate has dropped dramatically. However, there are approximately 2,500 infants who die of SIDS every year in the U.S., and SIDS is the third leading cause of infant mortality. In 2009, SIDS was responsible for 57 infant deaths in Illinois, compared with 106 infant deaths in 1999. SIDS occurs more often in males and in African-American and American Indian or Alaskan Native infants. More SIDS deaths occur in the colder months.

What Causes SIDS?

The cause(s) of SIDS is still unknown. However, it is generally accepted SIDS is a combination of factors or events. A leading theory is that an infant who appears to be healthy has an underlying defect located in the brain stem. This area in the brain controls heart and lung functions, including heart rate and breathing. SIDS studies indicate some babies have a delay in the development of or an abnormality in the part of the brain involved in breathing and waking. Babies born with this abnormality may be more vulnerable to sudden death.

Other factors also could play a role in SIDS. For example, if an infant with an underlying problem is exposed to other factors or stressors, such as secondhand smoke or sleeping on their stomach, the infant is at a higher risk of dying from SIDS.

Because the exact cause of SIDS remains unknown and there is no way of predicting which infants are at a higher risk, it is important to eliminate the risk factors that can be controlled. These factors include exposure to secondhand smoke, tummy sleeping and other unsafe sleep practices.

What are the SIDS Risk Factors?

  1. Infants who are placed on their sides or tummies at bed time or nap time
  2. Use of any soft or loose bedding, including quilts, heavy blankets and bumper pads
  3. Bed-sharing (both baby and adults or children sharing the same sleep surface, including beds or couches)
  4. Overheating or over-bundling the baby
  5. Maternal cigarette smoking during pregnancy and infant's exposure to secondhand smoke
  6. Little or no prenatal care
  7. Maternal age less than 20 years
  8. Premature or low birth weight babies

What can I do to Reduce the Risk of SIDS?

  1. Always place your baby on his or her back to sleep for bed time and nap time.
  2. Use a safety approved crib with a firm mattress. Drop side cribs should not be used. For information on crib safety standards, visit the Consumer Product Safety Commission's website at
  3. Remove all loose bedding, such as pillows, quilts, stuffed toys and other soft items from the crib.
  4. Don't let your baby become too warm.
  5. Make sure your baby's head is uncovered.
  6. Don't smoke while pregnant.
  7. Don't smoke around your baby and don't let anyone else smoke around your baby.
  8. Don't allow bed-sharing, even with siblings.
  9. Don't use bumper pads in cribs due to suffocation or strangulation hazards.
  10. Breastfeed your baby. Studies show breastfeeding can help reduce the risk of SIDS.
  11. Consider offering a pacifier after breastfeeding is established, at bed time and at nap time.
  12. Room-share with your baby, without bed-sharing.
  13. Don't use products claiming to reduce the risk of SIDS, including wedges and positioners.
  14. Take your baby for their well-child appointments, including vaccinations.
  15. Maintain a safe sleep environment – safety approved crib, fitted sheet and firm mattress.

Back to Sleep Campaign

It is important to remember there is no way to prevent SIDS. However, we do know babies sleep safer when placed on a firm surface on their back. The Back to Sleep Campaign was launched in 1994 to help inform parents and caregivers of the importance of back sleeping. Since the introduction of the Back to Sleep Campaign, the number of SIDS deaths has dropped by more than 50 percent nationwide. The campaign has since expanded to the Safe to Sleep Campaign to include recommendations for parents and caregivers on ways to reduce the risk of SIDS and to reduce the risk of other sleep-related causes of infant death, such as suffocation. For more information on the Safe to Sleep Campaign, visit the National Institute of Child Health and Human Development website at

American Academy of Pediatrics 2011 SIDS Policy Recommendations

In 2011, the American Academy of Pediatrics (AAP) revised its policy statement regarding SIDS based on recent research studies. Recommendations now include:

  • Back to sleep for every sleep until 1 year of life
  • Use a firm sleep surface, such as a crib mattress, covered by a fitted sheet
  • Room-sharing without bed-sharing is recommended
  • Keep soft objects and loose bedding out of the crib to reduce the risk of SIDS, suffocation, entrapment, and strangulation
  • Pregnant women should receive regular prenatal care
  • Avoid smoke exposure during pregnancy and after birth
  • Avoid alcohol and illicit drug use during pregnancy and after birth
  • Breastfeeding is recommended
  • Consider offering a pacifier at nap time and bedtime
  • Avoid overheating the baby
  • Infants should be immunized in accordance with recommendations of the AAP and the Centers for Disease Control and Prevention
  • Avoid commercial devices marketed to reduce the risk of SIDS
  • Do not use home cardiorespiratory monitors as a strategy to reduce the risk of SIDS
  • Supervised, awake tummy time is recommended to facilitate development and to minimize development of positional plagiocephaly

For more information on the American Academy of Pediatrics SIDS Policy Recommendations, visit

SIDS and Bed-Sharing

According to the American Academy of Pediatrics, bed-sharing is not recommended. Bed-sharing has not been found to be protective against SIDS, and bed-sharing increases the risk of accidental suffocation and overlay. However, room sharing may be protective against SIDS. Placing the baby in a safety approved crib or bassinet near the adult bed will allow parents to remain close to the baby while providing a safe sleep environment.

Can Vaccinations Cause SIDS?

Recent studies conclude routine vaccinations are not risk factors for SIDS. Because vaccinations typically begin at age 2-to-4 months, the peak age for SIDS, many people have associated vaccinations with the increased risk of SIDS. The association of vaccinations and SIDS has been studied for several years, and reports conclude routine vaccinations do not contribute to SIDS. In fact, infants who have been vaccinated have a decreased risk of SIDS.

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