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.
Although SIDS (also called crib death) is rare overall in the United States (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 month 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, African-American and Native-American infants have an increased risk of SIDS. 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.
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.
Doctors cannot make the diagnosis without an autopsy to rule out other causes of sudden, unexpected death (such as intracranial hemorrhage, meningitis, or myocarditis). Doctors also need to assess whether the infant suffocated or died as the result of abuse.
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. Avoiding overwrapping and protecting infants from overheating may also help. 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.
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 (visit www.sids.org), and support groups to assist parents.
Last full review/revision October 2012 by Elizabeth J. Palumbo, MD