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Sudden Infant Death Syndrome (SIDS)

Volume 4, Number 3 - April, 2000

Editors: Carol A. Rice, Ph.D., RN, Professor and Extension Health Specialist, and Janet M. Pollard, MPH, Extension Associate-Health

Inside HealthHints....

What is SIDS?

SIDS is a medical term that describes the sudden death of an infant which remains unexplained after all known and possible causes have been ruled out through autopsy, death scene investigation, and review of the medical history (SIDS Network, 1999c).

SIDS is not something that can be predicted by parent or physician. In fact, most children who die of SIDS appear healthy prior to death.

Sudden Infant Death Syndrome (SIDS), once known as crib death, claims the lives of thousands of babies each year...nearly one baby for every 1,000 live births. It is the major cause of infant deaths between one month and one year of age. In the last century, SIDS has claimed 150,000 victims in the United States alone. That's 7, 000 babies each year -- nearly one baby every hour of each day. SIDS is not discriminating; it strikes families of all races, ethnicities, and socioeconomic origins without warning (SIDS Network, 1998; SIDS Network, 1999c).

Effective January 1, 2000, all caregivers working with children age 24 months and younger must have one hour of special training combining the following three topics:

Specific training information can be found at the following Internet sites:

This issue of HealthHints is designed to help you educate others about SIDS -- what it is, what it is not, and what can be done to reduce the risk of SIDS.

What Causes SIDS?

We do not yet know how or why SIDS happens. Current theories include:

This can also be described using the triple-risk model, which describes the connection of events that may lead to SIDS. (Filiano, 1990)

SIDS risk model

The first element of the model is the critical development period. This period consists of the rapid growth phases during the infant's first six months of life which may periodically destabilize the infant's system. During this developmental period, changes occur in homeostatic controls, such as sleeping and waking, breathing, heart rate, blood pressure and temperature.

The second element of the model is the vulnerable infant. The vulnerable infant is an infant with an underlying defect or abnormality. In this model, normal babies do not die of SIDS; instead, there are pathophysiological reasons behind these seemingly sudden deaths, such as defects in regions of the brain that control respiration and heart rate during early life.

The third element involves exogenous stressors, outside or environmental challenges which a normal baby can overcome and survive, that an already vulnerable baby night not. Stressors such as second-hand exposure to tobacco smoke, prone sleep position (on the stomach) or upper respiratory infection alone do not cause death for the infant, but may pose an added, if not fatal risk to an infant who is already vulnerable (Filiano, 1990; SIDS Alliance, 2000).

In this model, all three elements must come together for SIDS to result (Filiano, 1990).

Currently, scientists are researching the development and function of the nervous system, brain, heart, breathing and sleeping patterns, balances of body chemicals, autopsy findings, and environmental factors. It is likely that SIDS, like many other medical disorders, will eventually have more than one explanation (SIDS Network, 1999c).

Common Characteristics of SIDS

Though we do not know the cause of SIDS, there are some common characteristics, that exist.

What SIDS is NOT

Though we don't know what SIDS is in terms of a cause, we do know what SIDS is not.

SIDS Risk Factors

Now that we have an idea what SIDS is and is not, as well as some of the characteristics of this condition, the question arises -- Can SIDS be prevented? Unfortunately, the answer is no, not yet. Recent research studies, however, have begun to isolate some factors that may play a role in some cases of SIDS deaths.

The following risk factors can be shared with parents and care providers in the hope of giving babies the best chance to thrive:

Back to Sleep

The rate of SIDS has dropped 43%, the equivalent of saving over 2,000 babies' lives a year since 1992 when physicians first recommended that babies be positioned on the Back To Sleep (SIDS Alliance, 1999b). Note: the AAP does not approve of restrictive devices to hold an infant's head in place. When an infant is able to easily turn over from the back to the stomach position, they should still be put to sleep on their backs, but then allowed to adopt whatever position they prefer (SIDS Network, 1999b).

In 1992, the American Academy of Pediatrics (AAP) released a statement recommending healthy infants be placed on their sides and backs, rather than on their stomachs (prone position). Recent reports indicate that the risk of SIDS is slightly higher for those placed on their sides compared to those on their backs (possibly because those on their sides are more likely to spontaneously turn to a stomach position). Both non-prone positions (side or back), however, are associated with a much lower risk of SIDS than the prone (stomach) position.

There are two exceptions to these recommendations:

  1. Infants with symptomatic gastroesophageal reflux, and
  2. Infants with certain upper airway malformations such as Robin Syndrome may be considered more stable when lying prone.

If there are concerns about either of these exceptions or other respiratory or sick-child concerns, a doctor should always be consulted.

In addition to these exceptions, when the Back to Sleep campaign was first released, some concerns were expressed about adverse events associated with back sleeping, such as flattened heads, poor sleeping, vomiting, or aspiration. Of studies performed regarding these concerns, only flat spots on the head and slight increase in diaper rash were found among those sleeping on their backs.

In light of the latest findings, however, the American Academy of Pediatrics has slightly modified their statement. The current recommendation are as follows:

  1. Infants should be placed for sleep in a non-prone position. A supine position (wholly on the back) confers the lowest risk and is preferred. However, a side position also carries a significantly lower risk than a prone position. If the side position is used, caregivers should be advised to bring the dependent arm forward, to lessen the likelihood of the baby rolling into a prone position.
  2. Soft surfaces and gas-trapping objects should be avoided in an infant's sleeping environment. Of particular importance, soft surfaces such as pillows or quilts should not be placed under a sleeping infant.
  3. The current recommendation is for healthy infants only. The pediatrician should consider the relative risks and benefits. Gastroesophageal reflux and certain upper airway anomalies that predispose to airway obstruction and perhaps some other illnesses may be indications for a prone sleeping position.
  4. The current recommendation is for infants during sleep. A certain amount of "tummy time," while the infant is awake and observed, is recommended for developmental reasons and to help prevent flat spots on the back of the head. The recommendations in this statement do not indicate an exclusive course of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate. Task Force on Infant Positioning and SIDS, 1996-1997 (SIDS Network, 1999b).

Smoke-Free Environment

Risk factors by themselves do not cause Sudden Infant Death Syndrome, but can have a negative effect on infant well-being...While doctors are hopeful that following the recommendations may reduce the risk of SIDS, we must understand that following the recommendations faithfully will still not prevent SIDS. Research must continue if we are to discover how and why SIDS occurs, and expand upon these and other risk factors (SIDS Network, 1999a).

SIDS has long been associated with women who smoke during pregnancy. A recent study by the National Center for Health Statistics showed that women who quit smoking during pregnancy, but resumed after the child's birth put their babies at risk, too. Findings from this study indicated that babies exposed to smoke only after birth were twice as likely to die from SIDS as those whose mothers did not smoke at all; constant smoke exposure during and after pregnancy tripled an infant's risk for SIDS (SIDS Network, 1999a).

In another study of cigarette smoke exposure, SIDS was related to both exposure to prenatal cigarette smoke and an impaired ability to arouse from sleep (Franco, 1999).

It is important to note, however, that the majority of infants who have been victims of SIDS do not have mothers who have smoked (Ariagno, 1994). Thus, as with all risk factors, the absence of smoke is not guaranteed protection or prevention.

Firm- and Soft-Bedding Issues

In response to the latest research the U.S. Consumer Products Safety Commission (CPSC) has advised parents to use a firm, flat mattress in a safety-approved crib for their baby's sleep. A series of advisories have been issued for parents on the hazards posed to infants sleeping on:

Second-hand, hand-me-down, and family heirloom cribs, cradles, mattresses, and other bedding may also impose safety hazards (SIDS Alliance, 1999b).

In addition to using a firm mattress, other soft bedding items should be eliminated as well:

Bedding that gets bunched up around or accidentally covers the face and head can block the airways. As many as 900 deaths attributed to SIDS each year may actually be caused by suffocation in soft bedding.

Note: Parents should also avoid using blankets or other soft coverings as a sun or weather screen, or to block out distractions or sound while their baby is napping.

Use light pajamas in warmer weather and warm sleepers in colder weather. If a blanket must be used, parents are urged to position their baby on his/her back in the lower 1/3 of the crib, babies feet pointing to the foot of the bed, and to secure the blanket under the sides of the mattress below the infant's armpits (SIDS Alliance, 1999b).

To help reduce this risk, the CPSC and seven major retailers are now joining forces in a campaign to prevent deaths from soft bedding. These seven retailers (Babies R Us, IKEA, JCPenney, Kmart, Lands' End, Sears, and Target) are making changes to their crib displays in retail stores, catalogs, advertisements, and websites. Beginning this Spring, shoppers will no longer find cribs made up with pillows and comforters at these retailers. Many retailers will be providing cautionary statements about soft bedding on their cribs, as well as in catalogs, advertisements, websites, and among bedding items a parent might purchase for their baby.

Avoid Overheating

Be careful not to overheat your baby, especially when your baby is ill. Research findings indicate that overheating (i.e., too much clothing, too heavy bedding, and/or too warm a room) may greatly increase SIDS risk for a baby with a cold or infection. Some signs that your baby may be overheating include:

Sometimes a fever may also indicate overheating.

To reduce risk of overheating, set your thermostat to the temperature that you find comfortable. Some pediatricians also recommend maintaining your indoor temperature at 68 to 70 degrees Fahrenheit to help your baby regulate his or her temperature, as well as dressing your child in as little or as much clothing as you would wear (SIDS Alliance, 1999b; SIDS Network, 1999b).

Note: In addition to your home environment, don't forget to remove hats and other coverings while in the car, store, etc. to avoid overheating.

Breastfeeding

To further reduce risk for SIDS, if possible, breastfeed your baby. Studies from the National Institute of Child Health and Human Development (NICHD) have shown that babies who died of SIDS were less likely to have been breastfed. Some of the potential advantages that a breastfed baby may have include prevention of:

Educating Caregivers

All caregivers, including baby sitters, child daycare providers, grandparents, aunts, uncles, etc. should be educated about SIDS risks. It is important not to assume that all care providers know about the Back to Sleep and other SIDS risk reduction recommendations.

Continuity of care is important in SIDS risk reduction, from parents to caregivers -- from nighttime to naptime (SIDS Alliance, 1999b).

Prenatal Care

Taking good care of yourself and your baby is of the utmost importance. By maintaining good prenatal care and communication with your health care provider, you can keep your provider informed about changes in your baby's health and behavior that may be of concern (SIDS Alliance, 2000).

Other Important Factors

Studies of SIDS victims have also been able to tell us some other important factors, which we may or may not have control over, in terms of reducing risk. Statistics have shown the following information:

Bed-sharing

One other factor that has been in the lime-light regarding SIDS is the issue of bed-sharing. Bed-sharing has not been proven to be protective against SIDS and, according to the American Academy of Pediatrics, may under some conditions be hazardous (SIDS Alliance, 2000).

The same recommendations for safe sleeping apply whether sharing a bed with your baby or putting him or her in a crib alone:

While bed-sharing can boost breast-feeding and promote a bond between mother and child, bed-sharing with other relatives, (e.g., brothers, sisters, etc.) other than the mother and father, is not recommended. When making your decision, consider discussing bed-sharing with your health care provider (SIDS Alliance, 2000).

Keeping Things in Perspective

When the American Academy of Pediatrics first began to issue recommendations for healthy babies to be placed on their backs to sleep, a whole new set of issues arose for parents and the health professionals to whom they turn for help. You can help to calm parents' fears and keep their babies sleep position and their infant care practices in perspective. Here are a few tips that may help:

Resource Extra!

Available through the Educational Resource Library: Back to Sleep (VHS 2370) -- video from the National Institute of Child Health and Human Development on reducing the risk.

Websites with Reliable Information

References

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