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Sudden Infant Death Syndrome: Causes, Risk Factors, And Prevention

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The sudden and unexplained death of an infant is called sudden infant death syndrome (SIDS). It may also be called crib death or cot death since it often occurs in a crib while the baby is asleep. Investigations of SIDS and medical history review do not usually reveal a discernible cause of the death.

Approximately 2,300 babies in the US succumb to SIDS each year, and it commonly affects infants between the ages of one and four months (1). There are several possible causes of SIDS. Thankfully, the risk of SIDS can be significantly reduced through simple safety precautions and lifestyle changes.

Read this post to know more about the causes and risk factors of sudden infant death syndrome and measures to lower the risk.  

Causes Of SIDS

The exact cause of SIDS is unknown (2). However, some theories suggest that it could occur due to the following reasons (1).

  • Problems in the baby’s ability to arouse from sleep
  • Failure of the baby’s brain centers to detect low oxygen and high carbon dioxide levels
  • High levels of carbon dioxide build-up in the blood

A combination of the above conditions and sleeping on sides or tummy may contribute to SIDS. When babies sleep on their stomach or their sides, they may breathe in the exhaled air since they are face down. It may increase the carbon dioxide levels in the blood that usually stimulates brain arousal and respiratory centers. It makes babies wake up, turn their heads, and breathe more oxygen. However, babies who fail to wake up may experience SIDS.

Another theory that explains SIDS’s cause is the simultaneous existence of the following three conditions, known as the “triple-risk model” (1).

  • The baby has brainstem anomalies causing the inability to respond to oxygen-carbon dioxide levels in the blood
  • There is a triggering factor such as sleeping on the tummy
  • The baby is less than six months old

These situations or factors could cause SIDS. However, there is no conclusive evidence since SIDS can occur in babies who are older than six months, have no brainstem anomaly, and do not sleep on tummy or sides. 

Factors That May Increase The Risk Of SIDS

Although the exact cause of death in SIDS is unknown, there are several factors likely to increase the risk of SIDS (3).

Sleep environmental risk factors include:

  • Sleeping on the stomach or sides
  • Overheating the room during sleep
  • Too soft sleep surfaces
  • Cribs with fluffy toys, bumper pads, and soft blankets
  • Sharing a bed with parents, siblings, or pets

Maternal risk factors include:

  • Three times more risk in cases of maternal smoking during pregnancy
  • Mothers younger than 20 at the time of first pregnancy or teen pregnancy
  • Maternal drug or alcohol use
  • Inadequate prenatal care
  • Multiple births during a short period

Physical factors may include:

  • Premature birth
  • Brain abnormality
  • Low birth weight
  • Respiratory infections – even just an upper respiratory infection
  • Exposure to secondhand smoke may double the risk 

Other factors that may increase the risk for SIDS include:

  • Sibling affected by SIDS
  • Family history of failure to thrive
  • Male babies have a higher risk
  • Age between two and four months
  • More incidence in fall, winter, and early spring months

When the above factors interfere with the baby’s breathing or cause other complications, it might lead to SIDS. Note that a combination of factors may be required to increase the risk of SIDS. 

Prevention Of SIDS

The American Academy of Pediatrics recommends the following precautions and lifestyle changes to mitigate the risk of SIDS (4) (5).

  • Put your baby on their back to sleep even for naps.
  • Let the baby sleep in the crib placed in the same room (room-sharing) where parents or caregivers sleep. However, do not share a bed with the baby.
  • Choose firm sleeping surfaces, like a firm mattress with an attached cover or sheet. A firm surface should be gentle yet hard enough to not indent.
  • Avoid keeping blankets, stuffed animals, dangling toys, pillows, or any other items in the baby’s crib.
  • If the baby falls asleep in a stroller, car seat, or infant carrier, then move them to their crib or a firm sleeping surface as soon as possible.
  • Maintain normal room temperature. If you want to keep the baby warm or the weather is warm, dress the baby appropriately.
  • Avoid smoking, alcohol use, and illicit drugs during pregnancy. Ensure proper prenatal care.
  • Avoid smoking around the baby, and try to quit the habit. Discourage others at home from smoking.
  • Breast feed for at least the first six months. Breastfed infants tend to have a lower risk of SIDS.
  • Offer a pacifier without string or strap after your baby is settled into a nursing routine by three to four weeks. Do not force the baby to use pacifiers or keep it back in their mouth if it falls while they are asleep.
  • Immunize according to the schedule to minimize the risk of infections. There is no scientific evidence that vaccination could cause SIDS.
  • Avoid the use of baby monitors and other devices that claim to prevent SIDS.

There is no definitive method to prevent SIDS since it does not have a precise cause. However, observing the above-mentioned precautions can substantially reduce the risk of SIDS. 

Diagnosis And Treatment Of SIDS

SIDS does not have any preceding symptoms, thus there is no prior diagnosis. SIDS is diagnosed as a cause of an infant’s death only when all the possible causes are excluded through a review of medical history and autopsy.

There is no specific treatment of SIDS. Observing precautions is the best way to minimize the risk. If your baby has any medical condition, then timely treatment may help reduce the risk of SIDS. Immunization and precautions can further safeguard the baby.

Despite the severity of the syndrome, you can do a lot to minimize the risk through precautionary measures. As the baby grows, their bodies become more robust and better adept at handling situations, which would have otherwise been the risk factors for SIDS.

It can be an emotional upheaval for parents who lost their baby to SIDS. Dealing with the investigation can be difficult for many, and they may often feel guilty. Remember, SIDS does not have a specific cause, so do not blame yourself or your partner for it. You may seek support from counselors, doctors, or from a support group to deal with it.

References:

1. Sudden Infant Death Syndrome (SIDS)- Symptoms & Causes; Boston Children’s Hospital
2. Sudden infant death syndrome; U.S. National Library of Medicine
3. Sudden infant death syndrome (SIDS); St. Clair Hospital
4. How to Keep Your Sleeping Baby Safe: AAP Policy Explained; American Academy of Pediatrics
5. How can I reduce the risk of SIDS?;The Eunice Kennedy Shriver National Institute of Child Health and Human Development