Employee & Community Health

SIDS FAQs: Learning more about Sudden Infant Death Syndrome

10/19/2017 by Dr. Maria Valdes

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Sudden Infant Death Syndrome (SIDS) causes great concern among new parents, in part because there seems to be no clear reason why these babies dies. There are no known ways to prevent SIDS, but there are effective ways to reduce some of the risks. 

What is SIDS?

SIDS is identified in infants less than a year old whose death cannot be explained by other causes, even after a thorough investigation that includes an autopsy, review of the infant's medical history and examination of where the baby died. 

When does it happen?

  • In 1980, SIDS occurred in 130.3 per 100,000 live births in the United States. In 2015 the rate had decreased to 29.3 per 100,000 live births. 
  • A search of records for infants who died in Olmsted County from 1945-1992 revealed 82 cases of SIDS. 
  • In 2015, approximately 1,600 infants died of SIDS in the U.S.
  • In 1992, the American Academy of Pediatrics recommended infants be placed on their backs for sleep. 
  • Males and nonwhite infants are at greater risk of SIDS. 
  • About 15-20% of SIDS happens in child-care settings. The median age for SIDS is 11 weeks, with a peak when babies are between two to four months old; 90% of cases take place before infants are six months old. 
  • It once was thought that SIDS increased during the winter, but it seems to happen evenly throughout the year. 

What causes SIDS?

There are many theories about the causes of SIDS. Some experts think an underlying brain-stem abnormality may make the baby more vulnerable to an event - such as if the mother smokes or gets an infection - during a critical period of the baby's central nervous system development. Another theory is that serotonin levels (a chemical produced by nerve cells) may play a role in SIDS. The hope is that one day there will be a screening or test for SIDS, but one is not available yet. 

What factors increase the risk of SIDS?

  • Mother younger than 20
  • Mother smokes or uses alcohol or substances during pregnancy
  • Late or no prenatal care
  • Pregnancy complications, such as premature rupture of membranes, placenta concerns, increased alpha fetoprotein levels in the mother
  • Preterm birth/low birthweight infants
  • Infants exposed to second-hand smoke
  • Sleeping on the stomach, sleeping on a soft surface or with bed accessories (toys, crib bumpers, blankets, pillows, etc.)
  • Bed sharing
  • Infant getting too warm or over heated

How can the risk of SIDS be reduced?

While we don't know how to prevent SIDS, there are ways to reduce some of the risks. However, some approaches, such as the use of home cardiorespiratory monitors, have not had an impact on reducing SIDS. Here are some things parents can do:

  • Don't use tobacco, alcohol or other substances during pregnancy or after birth. 
  • Be sure to get prenatal care early and throughout your pregnancy. 
  • Breastfeed your baby. 
  • Infants should sleep alone - no wedges or positioning devices, blankets, stuffed toys, bumper pads or pillows - on their back on a firm surface every time they sleep during the first year of life. Once they are able to roll over, they can stay in whatever position they assume. 
  • Do not share a bed, chair or sofa for sleeping. 
  • Have the baby in your room for at least the first six months of life or for up to a year. 
  • Keep the temperature in your infant's room comfortable for a lightly clothed adult. They shouldn't sleep in direct sunlight or in front of a heater or radiator.
  • Offer an unattached pacifier to an awake baby at nap time or bedtime. Do not replace it if it falls out when they're asleep. 
  • Do not swaddle infants who can roll over. 
  • Use car seats only for sleep while in a car. 
  • Be sure your baby receives their routine immunizations. 

Remember the ABCs

Infants should sleep Alone on their Backs in a Crib. 

Unfortunately, SIDS still happens, and when it does, it is devastating to the entire family. Parents may have feelings of loss and guilt. There is also the stress of dealing with the mandatory investigation that is done to determine the cause of death. 

Grief support groups are available for those who have lost an infant to SIDS. The Minnesota Sudden Infant Death Center offers resources and information for families and health care providers. 

Dr. Maria Valdes is a pediatrician in Employee and Community Health's (ECH) Division of Community Pediatric and Adolescent Medicine. She is a member of the Pediatric Knowledge board for AskMayoExpert and one of the authors of "Incidence of Sudden Infant Death Syndrome in Olmsted County, Minnesota 1945-1992", which was published in Mayo Clinic Proceedings.