Sudden infant death syndrome (SIDS) is the sudden, unexpected death of a seemingly healthy infant during sleep, in whom a thorough postmortem examination does not show a cause.

• The cause of 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 SIDS (also called crib death) is rare overall (about 1 in 2,000), it is one of the most common causes of death in infants between the ages of 2 weeks and 1 year. It most often affects children between the second and fourth month of life. The syndrome occurs worldwide. SIDS is more common among premature infants, those who were small at birth, those that previously needed resuscitation, and those with upper respiratory tract infections. For unknown reasons, black and Native American infants are at higher risk. It is more common among infants in families with low incomes; whose mothers are single, less than 20 years old, or who have used cigarettes or illicit drugs during pregnancy; and who have had brothers or sisters who have also died of SIDS.

Did You Know... Although rare, sudden infant death syndrom is one of the most common causes of death in infants between the ages of 2 weeks and 1 year.

The cause of 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. 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 soft bed also increases the risk of SIDS.

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. Parents should also remove pillows, bumper guards, and toys that could block an infant's breathing. Protecting infants from overheating may also help, but this measure is not proved. Preventing infants from breathing second-hand cigarette smoke may help and clearly has other health benefits.

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, and support groups to assist parents.

Back 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. Changing the direction that the infant lies in while in the crib each week and not leaving the infant in car seats, carriers, and bouncers too long also help.
Adapted from The National Institute of Child Health and Human Development, www.nichd.nih.gov.

Last full review/revision February 2009 by Elizabeth J. Palumbo, MD