It's the acronym that sends chills down the spine of every parent of a newborn: SIDS, a syndrome that is terrifying for its lack of explanation and for striking with seeming abandon.
Sudden Infant Death Syndrome accounts for the loss of some 2,500 babies each year in the United States, although the numbers could be higher, according to Dr. Betty McEntire, executive director of the American SIDS Institute in Marietta, Ga.
Particular attention is being paid to the syndrome, October being SIDS Awareness Month.
"A lot of babies die without an apparent cause, and when a medical examiner does the exam, they have to write it out as something," explains McEntire.
Established in 1983, the institute conducts research and promotes public awareness of SIDS.
"We're learning more every day, but we still haven't learned the final answer, which is the cause, and the way to get rid of it," the doctor adds.
'Back to Sleep'
Since the early 1990s, the American Academy of Pediatrics has fostered a campaign encouraging parents and caregivers to place infants 12 months and younger to sleep on their backs, rather than their stomachs, noting a significant decrease in the incidence of SIDS among back-sleeping babies. The rate of SIDS has dropped by more than 50 percent since that recommendation.
Even so, it remains the leading cause of death in infants.
"There's a theory called the Triple Risk Model, which says there could be a subtle defect in some infants that leads to SIDS, when combined with their vulnerable age and external factors, such as sleeping on their tummies, sleeping in bed with their parents, sleeping in a hot room or a too-quiet room," explains McEntire. "The problem is those defects are so subtle we can't even detect they're there."
At the National Institute of Child Health and Human Development in Bethesda, Md., the fruits of 25 years of research are coming to the fore, according to Dr. Marian Willinger, special assistant for SIDS.
"We've learned that the majority of babies who die of SIDS have some abnormality in their brain-stem nerve cells that use serotonin," she says. "This area of the brain stem controls how the baby responds to low oxygen and elevated carbon dioxide. It controls blood pressure, arousal -- everything involved in protective responses during sleep."
The problem is that no hard-and-fast screening tool exists to identify those babies.
"We can only detect this subtle finding by doing neurochemical studies on the brain after the baby has died," adds Willinger. "Right now, we're working on trying to identify those babies early, because if we can figure out what's going on, we may be able to intervene and prevent instances of SIDS."
SIDS can occur in any family -- all races and socioeconomic groups -- without warning, notes Dr. Steven Shapiro, chair of pediatrics at Abington Memorial Hospital, agreeing that, at times, a genetic predisposition can be uncovered.
Says Shapiro: "The discovery of Familial Dysautonomia, a disease most prevalent in Ashkenazi Jews, may be a factor in a SIDS baby. This is a disorder of the autonomic nervous system, and 85 percent of it can be found in Ashkenazi Jews."
Shapiro, who is also in private practice and a member of the Montgomery County Child Death Review Team, adds that in comparison to the United States, there are other cultures where SIDS does not exist.
"For example, there doesn't seem to be any incidences of SIDS in some of the tropical and Pacific Island countries. We looked at sleep cultures and sleep patterns, and found that all these babies were sleeping on their backs," he says. "Even in Japan, where babies are swaddled as they sleep on their backs or carried by their mothers in an upright position, the syndrome is almost unheard of."
For now, parents need to know four things about reducing the risk of SIDS, states McEntire: "Put your baby to sleep on his or her back for naps and at night; place the crib in your bedroom until your infant is at least 6 months old; leave the crib bare of anything, adding more layers of clothing for warmth rather than covers; and finally, don't expose your child to smoking, both before and after birth.
"If you do these things, the risk of SIDS is extremely low," she says.
Other cautionary measures in the prevention of SIDS include the use of pacifiers in the first year of life, breastfeeding, and early and regular prenatal and postnatal care. And according to a recent study from the Archives of Pediatrics & Adolescent Medicine, placing a fan in an infant's sleeping quarters increases air venillation, and thus could potentially decrease incidences of SIDS by as much as 75 percent.
Most SIDS-related deaths occur between the ages of 2- to 4-months old, with the numbers greater among boys than girls.
Rita Charleston contributed to this article.