Sudden Infant Death Syndrome

Sudden Infant Death Syndrome (also known as SIDS) refers to the sudden death of an apparently healthy infant under 1 year of age whose death cannot be explained even after a complete investigation.

Taking Care

Mrs. Wyatt is doing all the things her doctor told her to do with her new baby. She puts him to sleep for naps and at night on his back instead of on his stomach. She makes sure the crib has a mattress that is firm, and that there are no blankets, pillows, or toys around the baby. She refrains from bundling her baby in thick clothing before putting the baby to bed.

The doctor recommended these things because they reduce the risk of Sudden Infant Death Syndrome (SIDS), a mysterious disorder that is a leading cause of death for children between the age of 1 month and 1 year.

SIDS kills more than 3,000 babies a year in America, usually while they are asleep in cribs. But since mothers like Mrs. Wyatt started to put their babies to sleep on their backs, and to adopt other preventive strategies, the number of SIDS deaths has dropped more than 40 percent.

No one knows for sure why these babies die. Most of the babies appear to be healthy until their deaths.

Parents often feel guilt mixed with their grief over the death. They think perhaps there was something they could have done. But SIDS is no one's fault.

What Is SIDS?

Researchers have not discovered a cause for Sudden Infant Death Syndrome in the more than 30 years they have been studying it. In fact, it is easier to say what SIDS is not than what it is. SIDS does not result from suffocation, choking, vomiting, or a fatal reaction to a vaccination ^* . A baby does not catch it like a cold.

The only time doctors say that a baby has died of SIDS is if no other cause of death is found after there has been an autopsy ^* , an investigation of the place where the baby died, and a review of the baby's medical history.

Recent research suggests that infants who die of SIDS might have a problem in an area of the brain that controls two functions while they are asleep: breathing and waking up. This problem area in the brain, however, might not be enough on its own to cause SIDS. Other things may have to happen to reduce the amount of oxygen a baby gets, or to disrupt the baby's breathing and heart rate.

For example, babies might not get enough oxygen when they breathe air that is trapped in soft beds or in folds of blankets near their mouths. This is not the same as suffocation, which usually involves completely blocking a person's ability to take in air. In SIDS, the babies may be getting air but not enough oxygen, because they are breathing in their own exhaled breath.

Respiratory infections such as a cold or other ailment also can make breathing difficult for a baby.

Usually, babies would wake up and cry if they were not breathing well. But it may be that some babies cannot process the signals in the brain when they are not breathing properly.

These examples could help explain why babies who sleep on their stomachs or have infections are at higher risk of SIDS. It also might explain why SIDS is more likely to occur in the winter, when the risk of infection is higher and babies might be sleeping with more bedclothes or blankets.

Researchers are investigating other possible physical problems that could contribute to the risk of SIDS. One possible factor is an immune system ^* disorder that creates too many white blood cells and proteins, which disrupt the brain's control over breathing and heart rate.

Like many disorders, SIDS might have a combination of factors that cause it, including some that have not been discovered.

Who Is at Risk for SIDS?

Although research is beginning to suggest causes for SIDS, there is still no way to predict who will die of the disorder. The vast majority of babies who are laid to sleep on their stomachs, have infections, or sleep with blankets do not die from SIDS. Others who sleep on their backs in ideal conditions still die of the disorder.

There are no warning signs of SIDS before a baby dies. Doctors only diagnose it after ruling out other possible causes of death.

Certain things are known. SIDS can happen any time within the first year, but it occurs most often between the first and fourth month after birth. Seldom does it occur within the first 2 weeks following birth or after 6 months.

What Are the Risk Factors for SIDS?

A baby is more likely to die of SIDS if the baby has:

• A mother who smoked during pregnancy
• A mother less than 20 years old
• A mother who did not receive proper medical care before her baby was born
• A birth before the full 9 months of a normal pregnancy
• A lower than normal birth weight
• Family members who smoked around the baby.

However, babies who are breast-fed have a lower risk of SIDS than babies who are fed with a bottle. One possible reason might be because breast-feeding helps reduce the risk of the types of infections that may contribute to breathing problems.