Causes

The cause of SIDS is unknown. Many doctors and researchers now believe that SIDS is caused by several different factors, including:

• Problems with the baby's ability to wake up (sleep arousal)
• Inability for the baby's body to detect a build-up of carbon dioxide in the blood

SIDS rates have dropped dramatically since 1992, when parents were first told to put babies to sleep on their backs or sides to reduce the likelihood of SIDS. Unfortunately, SIDS remains a significant cause of death in infants under one year old. Thousands of babies die of SIDS in the United States each year. SIDS is most likely to occur between 2 and 4 months of age. SIDS affects boys more often than girls. Most SIDS deaths occur in the winter.

The following have been linked to a baby's increased risk of SIDS:

• Sleeping on the stomach
• Being around cigarette smoke while in the womb or after being born
• Sleeping in the same bed as their parents (co-sleeping)
• Soft bedding in the crib
• Multiple birth babies (being a twin, triplet, etc.)
• Premature birth
• Having a brother or sister who had SIDS
• Mothers who smoke or use illegal drugs
• Being born to a teen mother
• Short time period between pregnancies
• Late or no prenatal care
• Living in poverty situations

While studies show that babies with the above risk factors are more likely to be affected, the impact or importance of each factor is not well-defined or understood.

Symptoms

Almost all SIDS deaths occur without any warning or symptoms when the infant is thought to be sleeping.

Exams and Tests

Autopsy results are not able to confirm a cause of death, but may help add to the existing knowledge about SIDS. Autopsies may be required by state law in the event of unexplainable death.

Support Groups

Parents who have lost a child to SIDS need emotional support. Because no cause is found for the infant's death, many parents have guilty feelings. These feelings may be aggravated by investigations of police or others who, by law, must determine the cause of death.

A member of a local chapter of the National Foundation for Sudden Infant Death Syndrome may assist with counseling and reassurance to parents and family members. See: SIDS support group

Family counseling may be recommended to help siblings and all family members cope with the loss of an infant.

When to Contact a Medical Professional

If your baby is not moving or breathing, begin CPR and call 911. Parents and caregivers of all infants and children should be trained in CPR.

Prevention

Revised American Academy of Pediatrics' (AAP) guidelines, released in October 2005, recommend the following:

Always put a baby to sleep on its back. (This includes naps.) DO NOT put a baby to sleep on its stomach. Side sleeping is unstable and should also be avoided. Allowing the baby to roll around on its tummy while awake can prevent a flat spot (due to sleeping in one position) from forming on the back of the head.

Only put babies to sleep in a crib. NEVER allow the baby to sleep in bed with other children or adults, and do NOT put them to sleep on surfaces other than cribs, like a sofa.

Let babies sleep in the same room (NOT the same bed) as parents. If possible, babies cribs should be placed in the parents' bedroom to allow for night-time feeding.

Avoid soft bedding materials. Babies should be placed on a firm, tight-fitting crib mattress with no comforter. Use a light sheet to cover the baby. Do not use pillows, comforters, or quilts.

Make sure the room temperature is not too hot. The room temperature should be comfortable for a lightly-clothed adult. A baby should not be hot to the touch.

Offer the baby a pacifier when going to sleep. Pacifiers at naptime and bedtime can reduce the risk of SIDS. Doctors think that a pacifier might allow the airway to open more, or prevent the baby from falling into a deep sleep. A baby that wakes up more easily may automatically move out of a dangerous position. If the baby is breastfeeding, it is best to wait until 1 month before offering a pacifier, so that it doesn’t interfere with breastfeeding. Do not force a baby to use a pacifier.

Do not use breathing monitors or products marketed as ways to reduce SIDS. In the past, home apnea (breathing) monitors were recommended for families with a history of the condition. But research found that they had no effect, and the use of home monitors has largely stopped.

Other recommendations from SIDS experts:

• Keep your baby in a smoke-free environment.
• Breastfeed your baby, if possible. Breastfeeding reduces some upper respiratory infections that may influence the development of SIDS.
• NEVER give honey to a child less than 1 year old. Honey in very young children may cause infant botulism, which may be associated with SIDS.

Alternative Names

Crib death; SIDS

References

Task Force on Sudden Infant Death Syndrome. The Changing Concept of Sudden Infant Death Syndrome: Diagnostic Coding Shifts, Controversies Regarding the Sleeping Environment, and New Variables to Consider in Reducing Risk. Pediatrics. 2005 Nov;116 (5).

Hauck FR, Omojokun OO, Siadaty MS. Do Pacifiers Reduce the Risk of Sudden Infant Death Syndrome? A Meta-analysis. Pediatrics. 2005 Nov;116 (5).

Nelson EA, Yu LM, Williams S; International Child Care Practices Study Group Members. International Child Care Practices study: breastfeeding and pacifier use. J Hum Lact. 2005 Aug;21(3):289-95.

Kiernan MP, Beckerman RC. Is it sudden infant death syndrome or sudden unexpected infant death? Pediatrics. 2005 Sep;116(3):800-1.

Committee on Fetus and Newborn. American Academy of Pediatrics. Apnea, sudden infant death syndrome, and home monitoring. Pediatrics. 2003 Apr;111(4 Pt 1):914-7.

Sexton S, Natale R. Risks and benefits of pacifiers. Am Fam Physician. 2009. Apr 15;79(8):681-5.

Adams SM, Good MW, Defranco GM. Sudden infant death syndrome. Am Fam Physician. 2009 May 15;79(10):870-4.

Hunt CE, Hauck FR. Sudden Infant Death Syndrome. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 367.

Updated: 4/2/2012

Reviewed by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.