SUDDEN INFANT DEATH SYNDROME

DEFINITION

Sudden infant death syndrome (SIDS) is the unexplained death of an apparently healthy infant, usually during sleep. The condition is also known as crib death.

DESCRIPTION

Sudden infant death syndrome strikes 1 to 2 infants in every 1,000. It is the leading cause of death in newborn children. SIDS accounts for about 10 percent of deaths occurring during the first year of life.

SIDS most commonly strikes babies between the ages of two and six months. It almost never occurs in babies younger than two weeks or older than eight months. Most SIDS deaths occur between midnight and 8 A.M.

More than 4,800 babies died of SIDS in 1992. That number dropped to 3,279 deaths in 1995. One reason for this decrease was better education about the disorder. Parents were being taught to place babies on their backs or sides when put to bed, which is thought to reduce the risk of SIDS. In spite of this progress, doctors still have not determined the cause of SIDS.

CAUSES

While the exact cause or causes of SIDS are still unknown, one important factor may be infection of the respiratory (breathing) tract. Some studies show that many babies who die of SIDS had recently been treated for a cold or other respiratory illness. Most SIDS deaths occur during the winter and early spring. These seasons are the peak times for respiratory infections. Research suggests that the following factors may increase the risk of SIDS for a baby:

• The baby sleeps on his or her stomach.
• The baby's mother smoked during pregnancy.
• The mother was under the age of twenty at pregnancy.
• The mother abuses drugs.
• The mother received little or no prenatal (before birth) care.
• The baby was born prematurely (early) or with a low birth weight.
• The baby lives in house where someone smokes.
• The baby is male (SIDS is more common for infant boys that girls).
• Baby is a member of a minority or low-income family.
• Baby's family has a history of Sudden Infant Death Syndrome.

Theories about SIDS

Researchers have long been puzzled as to the actual cause of SIDS. While there are a number of theories to explain the condition, none of them have been proven. Doctors are often unable even to determine whether a baby died because of a heart problem or because it suddenly lost the ability to breathe.

Generally the theories focus on either medical disorders or the baby's physical surroundings.

MEDICAL DISORDERS. One theory about the cause of SIDS is that the baby's upper airway gets blocked. The baby suffocates because it can not get oxygen. Another theory is that the baby's blood has the wrong composition and may not contain enough of certain chemicals needed to keep the brain functioning.

A third theory is that SIDS babies have a faulty nervous system. Normally, infants have a mechanism that wakes them up when their oxygen supply is low. It could be that SIDS babies don't have that mechanism. Other theories blame SIDS on a faulty immune system or the buildup of certain chemicals called fatty acids in the baby's blood.

PHYSICAL SURROUNDINGS. Some researchers think SIDS may be caused by the way a baby sleeps. For example, it may be that a baby sleeps with its face in soft bedding or that the baby may be wrapped too tightly in blankets. Either of these situations can stop the baby from breathing properly or getting enough oxygen.

SYMPTOMS

SIDS does not have any warning symptoms. Death occurs suddenly and unexpectedly.

DIAGNOSIS

The diagnosis of SIDS is usually a diagnosis of exclusion. That means that all other possible causes of death are first ruled out. If no other cause of death can be found, then SIDS may be diagnosed.

Certain diagnosis of SIDS can be made only with an autopsy. An autopsy is a medical examination of a dead body. In about 20 percent of all SIDS cases, an autopsy shows a specific cause for death, such as suffocation. Parents sometimes reject the idea of having an autopsy on their baby, but the procedure can help explain how the baby died. Knowing the actual cause of death can help parents understand that the baby's death was no fault of their own.

TREATMENT

There is no treatment for SIDS. The best that can be done is to take action to prevent babies from dying of the condition. A baby's parents may, however, benefit from treatment including counseling and support from groups of other SIDS parents.

PREVENTION

At least some cases of sudden infant death syndrome can be prevented. Parents can take a number of actions that will reduce the risk of SIDS for their babies. These actions include the following:

• Sleep position. At one time, parents were taught to put their babies on their stomachs when they went to bed. That position was thought to prevent the baby from choking in its sleep. Experts now suggest that babies sleep on their backs or their sides. In these positions, they are less likely to have their faces covered in pillows and blankets.

Experts now suggest that babies sleep on their backs or their sides. In these positions, they are less likely to have their faces covered in pillows and blankets. (© 1993

Jan Halaska

. Reproduced by permission of

Photo Researchers, Inc.

)

• Good prenatal care. Women should get the best possible medical care while they are pregnant. This care will ensure that they are themselves healthy. Expectant mothers should be warned about the risks of smoking, alcohol intake, and drug use. A healthy mother's body is the best protection the newborn baby can have. Good prenatal care also involves education for the mother. She should be taught the best techniques for caring for her new baby.
• Proper bedding. Soft bedding, such as beanbags, waterbeds, and soft mattresses, increase the risk for SIDS. Babies should sleep on firm mattresses with no soft or fluffy materials near by. Soft stuffed toys should not be placed in a crib while the baby sleeps.
• Room temperature. A baby's room should be kept at a temperature that is comfortable for the parents. A baby who becomes too warm may sleep too deeply and may find it more difficult to wake up if it has trouble breathing.
• Diet. Some studies show that babies who are breast-fed are at lower risk for SIDS. Mother's milk may provide additional protection against infections that can cause SIDS in infants.
• Bed sharing with parents. Opinions differ as to whether bed sharing between mother and baby increases or decreases the risk of SIDS. Bed sharing may encourage breast-feeding, which decreases the risk of SIDS. Parents who bed share may also be more aware of any problems their baby has breathing. On the other hand, some studies show that bed-sharing increases the risk of SIDS. In any case, parents should remember cautions about the use of bedding if their babies sleep with them. They should also remember that an adult's bed does not have the same safety features of an infant's crib.
• Secondhand smoke. The baby's room should be kept free of tobacco smoke at all times.
• Electronic monitoring. Electronic devices are now available that allow parents to listen in while their baby is sleeping. These devices sound an alarm if the baby stops breathing. So far, however, there is no scientific evidence that electronic devices reduce the risk of SIDS. The U.S. National Institutes of Health recommends their use only for babies known to be at risk for SIDS. These babies include premature infants, infants who have had previous breathing problems, or infants with siblings who have died of SIDS.

FOR MORE INFORMATION

Books

Horchler, Joan Nelson, and Robin Rice Morris. The SIDS Survival Guide: Information and Comfort for Grieving Family and Friends and Professionals Who Seek to Help Them. Hyattsville, MD: SIDS Educational Services, 1997.

Sears, William. SIDS: A Parent's Guide to Understanding and Preventing Sudden Infant Death Syndrome. Boston: Little Brown & Company, 1996.

Organizations

Association of SIDS and Infant Mortality Programs. 630 West Fayette Street, Room 5–684, Baltimore, MD 21201. (410) 706–5062.

National Institute of Child Health and Development/Back to Sleep. 31 Center Drive, MSC2425, Room 2A32, Bethesda, MD 20892–2425. (800) 505–CRIB. http://www.nih.gov/nichd.

National SIDS Resource Center. 2070 Chain Bridge Road, Suite 450, Vienna, VA 22181. (703) 821–8955.

IDS Alliance. 1314 Bedford Avenue, Suite 210, Baltimore, MD 21208. (800) 221–7437.

Web sites

Child Secure. [Online] http://www.childsecure.com (accessed on November 4, 1999).