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What is SIDS

SIDS is the sudden, unexpected death of a child under one year of age, without identifiable cause, despite thorough investigation.

Sudden infant death syndrome has been defined as the “sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history” (Willinger, et al., 1991).

The risk worldwide ranges from 0.5 to 4 per thousand live-born children. There are between 6,000 and 7,000 cases of SIDS per year in the United States. SIDS usually occurs between the ages of 1 month and 1 year. The greatest number of cases are seen between 2 and 4 months of age.

By definition the cause is unknown, however because of the association with sleep position some investigators have proposed that position related alterations in respiratory mechanics, brain blood flow, disturbances in arousal mechanisms and sleep/wake regulation, or re-breathing of air may play a role. Postmortem observations suggest a pre-existing low-level, long-term, low oxygen level in the body.

SIDS Risk factors

Risk factors are biological and environmental factors that can influence illness. Risk factors do not cause illness.

  • Sleep position: Your infant should be placed on her back for sleeping. This should be continued throughout the first year. However, once your infant is rolling easily both from front to back and back to front (around 6 months), if she rolls out of position you do not need to replace her into the position. Other care providers should be reminded of the importance of sleep position (e.g. grandparents and daycare providers). There may be medical contraindications to back sleeping such as micrognathia or obstructive sleep apnea. These situations should be discussed individually with your infant’s physician. Preterm infants should also sleep on their back.
  • Temperature regulation. An increase in body temperature or environmental temperature is associated with SIDS. This is likely related to complex interactions between temperature regulation and cardiorespiratory control. It is best to keep the house between 68 and 70 degrees F, and do not overdress your baby. Dress the baby as you would dress yourself. If you are in a tee-shirt and shorts, put your baby in the equivalent.
  • An episode of apnea. If your infant has had an apparent life-threatening event (ALTE) he or she will be at increased risk for SIDS. An ALTE is an event where an infant stops breathing (apnea), turns blue and requires resuscitation.
  • Safe crib conditions: Make sure that your infant’s crib meets current safety criteria and has not been recalled by the consumer product safety commission. Use only a firm mattress and avoid bulky quilts, using only a single thin blanket if any at all. Infants should not sleep on surfaces not approved for infants such as pillows, sofas, bean bag chairs or waterbeds.
  • Smoking: If you smoked during pregnancy it is not too late to quit. Smoke exposure after your infant is born also increases SIDS risk, so quitting now will decrease this risk.
  • A sibling with SIDS. If there has been a previous sibling who died of SIDS, the risk for subsequent siblings is increased 4 to 5 times.
  • Prematurity. The risk of SIDS progressively increases as the birth weight decreases. It is currently not possible to determine which premature and low birth weight infants will die of SIDS.

SIDS Prevention

Studies and research are ongoing in the area of SIDS prevention. Researchers are trying to develop a screening test that will accurately identify those infants who will die of SIDS. Currently, a reliable method does not exist.

Home monitors, also called apnea monitors, are not indicated for all newborns. Home monitors tend to create more anxiety in parents as false alarms are frequent occurrences. Monitors are indicated for:

  • Infants who have had an episode of apnea (an apparent life-threatening event), without a known cause
  • Infants who are on home oxygen
  • Infants who have a sibling who has died of SIDS or a sibling who has had apparent life-threatening events
  • Premature infants who have episodes of apnea or bradycardia at the time of hospital discharge