Sudden Infant Death Syndrome
Alternate Names : SIDS, Crib Death
Sudden infant death syndrome, also known as SIDS, is the
sudden and unexplained death of an infant under one year of age. No cause
for the death can be found. Because many SIDS babies die in their cribs,
this syndrome is often called crib death. But cribs are not the cause
What is going on in the body?
SIDS is the leading cause of
death for babies between the ages of one month to one year. Most SIDS
deaths occur between age 2 and 4 months. Most SIDS
infants die silently, apparently in their sleep.
The good news is that, less than ten years ago, nearly twice
as many babies were dying of SIDS in the US as are today. This decrease
in SIDS is directly related to the campaign to educate parents to place
infants on their backs - instead of sides or stomachs - to sleep.
Current research is focused on the "triple-risk model." This
theory says that three things must happen at once for SIDS to occur:
The infant must have an underlying weakness in homeostatic
control. Homeostasis involves the vital functions. This includes
blood pressure, heart rate, respiration, chemoreception, upper airway
reflexes, and body temperature control. The baby's brainstem and nervous
system seem to be the key factors in homeostatic control.
The infant must be in a critical development period for
homeostatic control. This critical period is thought to be within
the first six months of life, when the baby's body and its systems are
An external stressor increases how vulnerable the
infant is to the homeostatic control issues. The most common
external stressor appears to be the stomach sleeping position. Other
factors may include soft bedding, infection, and fever.
This theory is still being tested, but evidence so far seems
to strongly support it. Many studies are going on today, and experts hope
to have more answers soon about what causes SIDS and who is at risk
What are the causes and risks of the condition?
While there are known risk factors for SIDS, none of these
factors clearly points to a distinct cause for SIDS. Many of these factors
are also risk factors for the sudden death of infants from other, known
causes. Risk factors linked with a higher rate of SIDS include:
Age of the child. Most cases occur in infants between one and
four months of age. Ninety-five percent of cases occur in infants six
months of age or younger.
Being part of a multiple birth. Twins or triplets are at greater risk
Being wrapped in blankets during sleep or sleeping on too soft
Exposure to tobacco smoke in the baby's environment.
Having a recent viral illness, such as an upper respiratory infection or
Low Apgar score
at birth. The Apgar score is a measure of how well an infant adapts
to life outside the womb in the first five minutes after birth.
Male gender. Boys die of SIDS slightly more often than girls.
Being born early and having a low birth weight are both risk factors
Sleeping on the stomach.
Sharing a crib or bed with another child.
Sharing a bed with a parent, when parents smoke or have recently
consumed alcohol or used drugs.
Being African American, American Indian, or Alaskan Native. All of
these ethnic groups have at least twice the risk for SIDS.
In addition, research has found risk factors in the mother
that may lead to an increased incidence of SIDS. These factors
include the following:
being unmarried, young, or poor
having had a large number of pregnancies
having pregnancies less than 12 months apart
lack of prenatal care
use of illicit drugs, especially cocaine, during pregnancy
binge drinking of alcohol during pregnancy