The death of a healthy baby is the worse tragedy parents can face, leaving them with a melancholy that may last throughout their lives. Since doctors can not tell them why their baby died, they blame themselves and often other innocent people. And if the condition is misdiagnosed as child abuse then things can get really dicey.

Sudden Infant Death Syndrome, also known as SIDS or "crib death" is the death of an infant under one year of age which remains unexplained after a thorough investigation, which should include a complete autopsy, examination of the death scene, and clinical history review. SIDS can neither be predicted or prevented. However, there are precautions that can be done to reduce the risk of SIDS.

SIDS is classified as a natural cause of death. It is the leading cause of death in the United States among infants between one month and one year of age. For all infants less than one year of age, SIDS is the third-leading cause of death, following only congenital anomalies and short gestation/low birthweight. The official rate from the National Centers for Health Statistics is roughly one death for every 2,000 live births -- or .05 percent, but the rate is probably much higher.

A diagnosis of SIDS is essentially an exclusionary diagnosis, one that is made by ruling out all other possible causes and then recognizing the distinctive patterns of this cluster of events. The process is expensive, and many counties don't have the resources to conduct such thorough investigations, resulting in a multitued of misdiagnosed cases.

Some medical examiners simply ascribe a cause based on circumstantial evidence. For example, when a baby is found lying on her tummy -- or in a bed with adults, or a crib full of soft toys -- the coroner can't rule out the possibility that the baby was accidentally smothered and may call it "possible accidental asphyxia" or "threats to breathing" rather than SIDS. That's why some states today report no SIDS deaths at all, despite the fact that babies still die there every year, says Fern R. Hauck, M.D., associate professor of family medicine and public health sciences at the University of Virginia. Then there's a phenomenon called code-shifting, which can happen if the examiner discovers a possibly unrelated underlying condition as well.

Code-shifting helps to explain why reported SIDS deaths have dropped in the past 14 years while other sudden infant deaths, like those attributed to accidental suffocation or even, simply, undefined causes, have increased significantly. This makes it nearly impossible for researchers to get an accurate assessment on what's realy happening with rates and risk factors right. That's why parents need to follow the latest safe-sleep recommendations to substantially reduce the rsik of SIDS."

However, research indicates that a simple best sleep practice of having babies sleep on their backs drastically reduces SIDS mortality. "By changing sleep positions in the past 10 years, there has been more than a 60 percent drop in cases of SIDS across the world," said Dr. Ann Halbower, a pediatric sleep-disorders expert at Children's Hospital Denver.

Although much remains to be learned, scientists do have some answers. SIDS is a sudden and silent killer, often associated with sleep, but apparently involving no suffering.

Approximately 60 percent of all SIDS deaths are those of male infants. Approximately 70% of SIDS mortality occurs in infants between two and four months of age, with nearly 90% taking place by six months of age.

In terms of social, racial, and other categories, SIDS appears in families from all social groups. African-American and Native American babies are at particular risk. Certain cultural behaviors contribute to high incidences of SIDS. For example, African-American mothers are "still significantly more likely to place their infants prone" (Willinger, et al. 1998, p. 332) and have adults and children sleeping in the same bed.

Most pediatricians concede that when babies are placed on their stomachs, they tend to sleep better, they are less apt to startle and they often sleep through the night sooner. However, infants who sleep on their stomachs face the greatest risk of SIDS. Unfortunately, this critical information is not being disseminated by many pediatricians and hospital staff. A case in point, a 2002 study in the journal Pediatrics found that preterm infants in intensive-care nurseries were frequently placed on their stomachs, and became accustomed to the position. "You'd be surprised how many parents come in here and hear the message for the first time," said Dr. Halbower.

To lessen the probability of babies developing plagiocephaly, a deformation of the skull that leaves infants with flattened heads, Dr. Jeffrey Wisoff an associate professor of neurosurgery and pediatrics at New York University Medical Center, recommends telling parents to turn infants 180 degrees in their cribs occasionally and to place them on their stomachs while they are awake (a practice known as "tummy time").

Babies overdressed or covered in blankets are at risk (characteristically, SIDS deaths show a pronounced peak during the colder months of the year and may be related to this risk factor).

Exposure to secondhand smoke raise the odds for all babies and new research says smoking during pregnancy has substituted sleeping on stomach as the major SIDS risk factor. It's estimated that 15 to 25% of preggies in western nations smoke all through pregnancy.

Epidemiological studies suggest that SIDS is somehow associated with a detrimental prenatal environment. In general, at-risk infants include premature babies, those with low birthweight or low weight gain and those whose mothers are less than twenty years of age, were anemic, had poor prenatal care, smoked cigarettes or used illegal drugs during pregnancy, and had a history of sexually transmitted disease or urinary tract infection.

When a baby's face is turned toward the bedding, he's in a position to re-breathe the carbon dioxide he exhales, which limits the amount of oxygen he takes in. Most babies will do something to change their environment...they'll turn their heads, or sigh, or yawn," says Rachel Moon, M.D., an associate professor of pediatrics at George Washington University School of Medicine. "But babies who die of SIDS don't wake up when they get into trouble, and we don't fully understand why." One of the more plausible theories centers on a brain-stem abnormality that affects the brain's ability to make and use serotonin -- and it may be responsible for well over half of all cases (Researchers at Boston's Children's Hospital).

Other genetic anomalies that may contribute to SIDS: A metabolic disorder called MCADD (medium chain acyl-CoA dehydrogenase deficiency). It impairs the baby's ability to process fatty acids, eventually causing a sudden and fatal interruption in heart function. Another condition is long QT syndrome, an electrical disorder in the heart that causes sudden bursts of extremely rapid heartbeats and can lead to cardiac arrest. MCADD and long QT syndrome account for fewer than 15 percent of SIDS cases, but both disorders can be successfully treated if caught in time by a blood test; unfortunately, these tests aren't routine in most states.

There are some biological, clinical, and circumstantial markers commonly found in this syndrome. These common but not universal markers include: tiny red or purple spots (minute hemorrhages or petechiae) on the surface of the infant's heart, in its lungs, and in its thymus; an increased number of star-shaped cells in its brain stem (brain-stem gliosis); clinical suggestions of apnea or pauses in breathing and an inability to return to normal breathing patterns. Markers such as these, when identified by a competent, thorough, and experienced physician, justify recognizing SIDS as an official medical diagnosis of death.

Preliminary research also suggests that babies who begin daycare before 4 months of age are at risk. "It may be that starting a new routine interrupts the baby's sleep cycle, so that when he finally does fall asleep, he sleeps too deeply," says Dr. Moon, M.D., an associate professor of pediatrics at George Washington University School of Medicine.

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