Learning about SIDS: FAQs – What Do We Know About SIDS?
What Is SIDS?
Sudden Infant Death Syndrome (SIDS) is the "sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history" (Willinger et al., 1991).
What is SIDS? (English)
Que es SMIS? (Spanish)
What are the Most Common Characteristics of SIDS?
Most researchers now believe that babies who die of SIDS are born with one or more conditions that make them especially vulnerable to stresses that occur in the normal life of an infant, including both internal and external influences. SIDS occurs in all types of families and is largely indifferent to race or socioeconomic level. SIDS is unexpected, usually occurring in otherwise apparently healthy infants from 1 month to 1 year of age. Most deaths from SIDS occur by the end of the sixth month, with the greatest number taking place between 2 and 4 months of age. A SIDS death occurs quickly and is often associated with sleep, with no signs of suffering. More deaths are reported in the fall and winter (in both the Northern and Southern Hemispheres), and there is a 60-to-40 percent male-to-female ratio. A death is diagnosed as SIDS only after all other causes of death have been eliminated: SIDS is a diagnosis of exclusion.
How Many Babies Die From SIDS?
The National Center for Health Statistics reports 2,151 deaths due to SIDS in the U.S. in 2001 (preliminary data). From year to year, the number of SIDS deaths tends to remain constant despite fluctuations in the overall number of infant deaths.
When considering the overall number of live births each year, SIDS remains the leading cause of death in the United States among infants between 1 month and 1 year of age and is second only to congenital anomalies as the leading overall cause of death for all infants less than 1 year of age.
How Do Professionals Diagnose SIDS?
Often the cause of an infant death can be determined only through a process of collecting information, conducting sometimes complex forensic tests and procedures and talking with parents and physicians. When a death is sudden and unexplained, investigators, including medical examiners and coroners, use the special expertise of forensic medicine (application of medical knowledge to legal issues). SIDS is no exception.
The autopsy provides anatomical evidence through microscopic examination of tissue samples and vital organs. An autopsy is important because SIDS is a diagnosis of exclusion. A definitive diagnosis cannot be made without a thorough postmortem examination that fails to point to any other possible cause of death. Also, if a cause of SIDS is ever to be uncovered, scientists will most likely detect that cause through evidence gathered from a thorough pathological examination.
A Thorough Death Scene Investigation
A thorough death scene investigation involves interviewing the parents, other caregivers, and family members; collecting items from the death scene; and evaluating that information. Although painful for the family, a detailed scene investigation may shed light on the cause, sometimes revealing a recognizable and possibly preventable cause of death.
Review of the Victim and Family Case History
A comprehensive history of the infant and family is especially critical to determine a SIDS death. Often, a careful review of documented and anecdotal information about the victim’s or family's history of previous illnesses, accidents or behaviors may further corroborate what is detected in the autopsy or death scene investigation.
Investigators should be sensitive and understand that the family may view this process as an intrusion, even a violation of their grief. It should be noted that, although stressful, a careful investigation that reveals no preventable cause of death might actually be a means of giving solace to a grieving family.