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Sudden Infant Death Syndrome (SIDS)


Christopher P. Raab

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Full review/revision Aug 2021 | Modified Sep 2022
Topic Resources

Sudden infant death syndrome is the sudden, unexpected death, usually during sleep, of a seemingly healthy infant 1 year of age or younger.

  • The cause of sudden infant death syndrome (SIDS) is not known.

  • Putting infants to sleep on their back; removing pillows, bumper guards, and toys from the crib; protecting infants from overheating; and preventing infants from breathing second-hand cigarette smoke may help prevent SIDS.

  • Parents who have lost a child to SIDS should seek counseling and support groups.

Although sudden infant death syndrome (SIDS; also called crib death) is rare overall in the United States (about 1 in 1,000 births), it is one of the most common causes of death in infants between the ages of 2 weeks and 1 year. African American and Native American children have twice the average risk of SIDS. It most often affects children between the second month and fourth month of life. The syndrome occurs worldwide. There are many risk factors.

Risk factors for sudden infant death syndrome

Children who have or who are exposed to any of the following risk factors are at increased risk of SIDS:


The cause of sudden infant death sydrome (SIDS) is unknown. It may be due to an abnormality in the control of breathing. Some infants with SIDS show signs of having had low levels of oxygen in their blood and having had periods when they stopped breathing (called apnea).

Laying infants down to sleep on their stomach and the use of soft bedding (such as pillows and lamb’s wool blankets) have been linked to SIDS. Sleeping together with an infant on a sofa, cushion, or bed (see Co-sleeping Co-sleeping Because the nervous system of newborns is immature, newborns sleep a great deal, but only for an hour or two at a time, regardless of whether it is day or night. By 4 to 6 weeks of age, many... read more ) also increases the risk of SIDS.

Did You Know...

  • Although rare, sudden infant death syndrome (SIDS) is one of the most common causes of death in infants between the ages of 2 weeks and 1 year. It is associated with laying infants down to sleep on their stomach.



  • Putting infants to sleep on their back

Despite the known risk factors for SIDS, there is no certain way to prevent it. However, certain measures seem to help, particularly putting infants to sleep on their back on a firm mattress. The number of SIDS deaths has decreased dramatically as more parents have put their infants to sleep on their back (see the Safe to Sleep® campaign). Parents should also remove pillows, bumper guards, and toys that could block an infant's breathing. Avoiding overwrapping and protecting infants from overheating may also help. Breastfeeding Breastfeeding Breast milk is the ideal food for newborns. Although babies may be fed breast milk or formula, the World Health Organization (WHO) and American Academy of Pediatrics (AAP) recommend exclusive... read more Breastfeeding and preventing infants from breathing second-hand cigarette smoke may help and clearly have other health benefits.

There is no evidence that at-home breathing monitors reduce the risk of SIDS.

Safe to Sleep: Reducing the Risk of Sudden Infant Death Syndrome

  • Position: Always place the infant on the infant’s back to sleep, for naps and at night.

  • Surface: Place the infant on a firm sleep surface, such as a safety-approved crib mattress, covered by a fitted sheet.

  • Bedding: Keep soft objects, toys, blankets, and other loose bedding out of the infant’s sleep area.

  • No smoking: Do not allow smoking around the infant. Not smoking during pregnancy is also important.

  • Location: Set up the infant’s sleep area close to but separate from the sleep area of the parents and other children.

  • Pacifiers: Consider offering the infant a clean, dry pacifier when placing the infant down to sleep.

  • Temperature: Do not let the infant overheat during sleep.

Home monitors and products that claim to prevent sudden infant death syndrome do not seem helpful.

To help prevent flat spots from developing on the infant's head, infants should spend some time on their tummy when they are awake and someone is watching them. To help make the infant's head round, parents should change the direction that the infant lies in while in the crib each week and avoid leaving the infant for too long in car seats, carriers, and bouncers.

Adapted from The National Institute of Child Health and Human Development (Safe to Sleep® campaign).

Resources for Parents Who Have Lost an Infant to SIDS

  • Counseling

  • Support groups

Most parents who have lost an infant to SIDS are grief-stricken and unprepared for the tragedy. They usually feel guilty. They may be further traumatized by investigations conducted by police, social workers, or others. Counseling and support from specially trained doctors and nurses and other parents who have lost an infant to SIDS are critical to helping parents cope with the tragedy. Specialists can recommend reading materials, web sites (such as the American SIDS Institute), and support groups to assist parents.

More Information

The following are some English-language resources that may be useful. Please note that THE MANUAL is not responsible for the content of these resources.

  • Safe to Sleep®: Information for parents and caregivers about safe sleep practices for infants

  • American SIDS Institute: An organization providing education about causes of and ways to prevent SIDS and family support services

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