Sudden Infant Death Syndrome

National Organization for Rare Disorders, Inc.

Skip to the navigation


It is possible that the main title of the report Sudden Infant Death Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • SIDS
  • cot death
  • crib death

Disorder Subdivisions

  • None

General Discussion

Sudden infant death syndrome (SIDS) is the sudden death of an infant under the age of 1 year that remains unexplained after careful review of the history, death scene investigation, and thorough autopsy. In 2008, the most recent published data from the National Vital Statistics System indicated that SIDS was listed as the third leading cause of death in infants in the United States. Causes of SIDS are considered to be multifactorial. The triple risk hypothesis describes the presence of three risk factors that, when overlapping, predispose a baby to SIDS. These include an environmental trigger/stress, a critical developmental period, and an underlying vulnerability. Physician-scientists and scientists are studying neuropathological tissue and genetic material from SIDS victims to ascertain factors that might be responsible for heightening an infant's vulnerability to SIDS. Others are performing physiologic studies on infants known to have an increased risk for SIDS. Basic scientists are studying animal models that might provide insight into mechanisms responsible for SIDS. Current clinical management targets improving education for families and caregivers regarding known modifiable environmental stressors (risk factors) (see below).


There are typically no symptoms prior to a SIDS death. Though SIDS occurs during sleep, the deaths may occur during day or night time sleep. Existing literature does not indicate any evidence for suffering by the infant in the moments preceding the sudden death.


By definition, the cause of SIDS is unknown. Therefore, the existing research addresses modifiable environmental risk factors, neuropathological and genetic factors that may predispose to SIDS, potential physiologic markers in at-risk infants, and animal modeling.

The American Academy of Pediatrics summarizes modifiable environmental factors with current recommendations for reducing the risk of SIDS. The focus is on modification of sleep position, sleep environment, and nicotine exposure. Infants should be placed to sleep in the supine position (on her or his back). The "Back to Sleep" NICHD campaign in 1994 encouraged parents to place their infant to sleep on their back or side, then the AAP campaign in 1996 recommendation that "back is best" (no side sleeping) led to a significant decrease in SIDS. The risks of supine sleep are positional plagiocephaly (malformation of the skull related to position) which can be decreased by giving the infant "tummy time" while awake, avoiding prolonged periods of time in car seats or bouncy chairs, and encouraging upright "cuddle time." Modifications of sleep environment include placing the infant to sleep on a firm surface without soft bedding, blankets or toys, placing the infant to sleep in the same room as the parent without bed-sharing, and in a bedroom with temperature that is comfortable for a lightly clothed adult. If an additional blanket is to be used, it should be placed on the infant so that the sheet reaches only to the infant's chest and is tucked in around the crib mattress to prevent it from covering the baby's face. The rationale is that these actions may reduce the chance of suffocation and overheating for the infant. Offering a pacifier at the onset of sleep is associated with decreased SIDS risk, but pacifier use should be delayed until after 1 month of age if the baby is breastfeeding and should not be reintroduced into the baby's mouth after (s)he falls asleep. Smoking or second hand exposure for the pregnant woman, new mother, and baby should be avoided to reduce SIDS risk and for many other health reasons.

Though the cause for SIDS is unknown, there has been much investigation into the pathophysiology (functional changes due to disease) and neuropathology (study of brain disease and diseases of the nervous system) of SIDS with many thoughts regarding the underlying problems that may make an infant vulnerable. Considering this, the etiology of SIDS is thought to include, but is not limited to, serotonergic system dysfunction, autonomic nervous system dysfunction, and impaired arousal mechanisms. All of these are inter-related in the baby's developing nervous system. Serotonin is a neurotransmitter (brain chemical involved in neuron-cell signaling) that has influence over a broad range of functions such as the sleep-wake cycle, thermoregulation, cardiovascular control, and modulation of motor activity. Neuropathological studies have found a decrease in serotonergic receptor binding in the medulla (area of the brain important for homeostatic function) of SIDS victims. Further, the serotonergic system has been found to be abnormal in 50% of SIDS cases. These findings have led to candidate gene studies, primarily based on clues from the neuropathological findings in SIDS victims and the limited clinical information documented before the sudden death; thus far, findings in the serotonergic system and genes expressed in the early embryology of the autonomic nervous system have not identified variations strongly associated with SIDS risk. Testing of additional genes, in larger cohorts, is currently under way.

Affected Populations

SIDS can affect all infants under 1 year of age. Most deaths occur less than 6 months of age with the peak affected age between 2 and 4 months. Gender, ethnic and racial differences also exist. For example, boys are at greater risk for SIDS than girls. Also, the SIDS rate in African American infants is 2.7 times greater than the Caucasian rate in the US. Likewise, SIDS rates are increased in the American Indians and Alaskan natives as compared to Caucasians. These differences may reflect both cultural practices and genetic variations.

Standard Therapies


SIDS is a diagnosis of exclusion which means that it is only determined as the cause of death after thorough investigation of clinical history, scene of death, and autopsy reveal no other cause.


Apnea or cardiac monitors have not been found to be useful in preventing SIDS. They serve to alert a caregiver to a potentially life threatening event. However, an infant can experience significant hypoxemia (reduced oxygen content) or abrupt bradycardia (slow heart rate) before the alarm is activated.

Because the diagnosis of SIDS is made after death, there is no treatment. The current recommendations are aimed at reducing risk factors that are associated with SIDS.

Investigational Therapies

SIDS parents have the opportunity to contribute tissue to the NICHD-funded University of Maryland Brain and Tissue Bank. Parents are encouraged to donate tissue within 24 hours of death. For further information, please go to:

The aim of the genetic and neuropathological studies is to design intervention strategies to avert the sudden death of these seemingly normal infants.

Information on current clinical trials is posted on the Internet at All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010


For information about clinical trials sponsored by private sources, contact:

For more information on SIDS, congenital central hypoventilation syndrome, and/or PHOX2B testing, please contact:

Pallavi P. Patwari, M.D.

Assistant Professor of Pediatrics at Northwestern University Feinberg School of Medicine

Center for Autonomic Medicine in Pediatrics (C.A.M.P.)

Ann & Robert H. Lurie Children's Hospital of Chicago

225 East Chicago Avenue, Box 165, Chicago, Illinois 60611-2605

Chicago, Illinois 60611-2605

phone: 312-227-3300

fax: 312-227-9606


web address:

Casey M. Rand, B.S.

Senior Project Coordinator

Ann & Robert H. Lurie Children's Hospital of Chicago

225 East Chicago Avenue, Box 165, Chicago, Illinois 60611-2605

Chicago, Illinois 60611-2605

phone: 312-227-3300

fax: 312-227-9606


web address:

Debra E. Weese-Mayer, M.D.

Professor of Pediatrics at Northwestern University Feinberg School of Medicine

Director, Center for Autonomic Medicine in Pediatrics (C.A.M.P.)

Ann & Robert H. Lurie Children's Hospital of Chicago

225 East Chicago Avenue, Box 165, Chicago, Illinois 60611-2605

Chicago, Illinois 60611-2605

phone: 312-227-3300

fax: 312-227-9606

e-mail: DWeese-Mayer@

web address:

web information on CCHS:



Klaver E.C., Versluijs G.M., Wilders R. Cardiac ion channel mutations in the sudden infant death syndrome. Int J Cardiol. 2011;152:162-170.

Weese-Mayer DE, Berry-Kravis EM, Ceccherini I, Keens TG, Trang H. An official American Thoracic Society clinical policy statement: Congenital central hypoventilation syndrome: Genetic basis, diagnosis, and management. Am J Respir Crit Care Med. 2010;181:626-644.

Kinney H.C. Brainstem mechanisms underlying the sudden infant death syndrome: evidence from human pathologic studies. Dev Psychobiol. 2009;51:223-233.

Franco P, Groswasser J, Scaillet S, et al. QT Interval Prolongation in Future SIDS Victims: A polysomnographic study. Sleep 2008; 31(12):1691-1699.

Weese-Mayer DE, Berry-Kravis EM, Ceccherini I, Rand CM. Congenital central hypoventilation syndrome (CCHS) and sudden infant death syndrome (SIDS): Kindred disorders of autonomic regulation. Respir Physiol & Neurobiol. 2008;164:38-48.

Martin JA, Kung HC, Mathews TJ, et al. Annual Summary of Vital Statistics: 2006. Pediatrics. 2008;121(4):788-801.

Weese-Mayer DE, Ackerman MJ, Marazita ML, Berry-Kravis EM. Sudden infant death syndrome: Review of implicated genetic factors. Am J Med Genet. 2007;143A:771-788.

Paterson DS, Trachtenbert FL, Thompson EG, et al. Multiple serotonergic brainstem abnormalities in the Sudden Infant Death Syndrome. JAMA. 2006;296:2124-2132.

Hoyert DL, Heron MP, Murphy SL, Kung HC. Deaths: Final Data for 2003. Natl Vital Stat Rep. 2006;54(13): 1-120.

Tomashek KM, Qin C, Hsia J, et al. Infant Mortality trends and differences between American Indian/Alaskan Native infants and white infants in the United States, 1989-1991 and 1998-2000. Am J Public Health. 2006;96:2222-2227.

Krous HF, Chadwick AE, Crandall L, Nadeau-Manning JM. Sudden unexpected death in childhood: A report of 50 cases. Pediatr & Devel Pathol. 2005;8:307-319.

American Academy of Pediatrics 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;116(5):1245-1255.

Kinney HC, Randall LL, Sleeper LA, et al. Serotonergic brainstem abnormalities in Northern Plains Indians with the sudden infant death syndrome. J Neuropathol Exp Neurol. 2003;62:1178-1191.

Ozawa Y, Okado N. Alterations of serotonergic receptors in the brainstems of human patients with respiratory disorders. Neuropediatrics. 2002;33:142-149.

Panigrahy A, Filiano J, Sleeper LA, et al. Decreased serotonergic receptor binding in rhombic lip-derived regions of the medulla oblongata in the sudden infant death syndrome. J Neuropathol Exp Neurol. 2000;59:377-384.

Schwartz PJ, Stramba-Badiale M, Segantini A, et al. Prolongation of the QT interval and the sudden infant death syndrome. NEJM. 1998;338:1709-1714.

Filiano JJ, Kinney HC. A perspective on neuropathologic findings in victims of sudden infant death syndrome: the triple-risk model. Biol Neonate. 1994;65(3-4):194-197.

Jacobs BL, Azmitia EC. Structure and Function of the Brain Serotonin System. Physiol Rev. 1992;72(1):165-229.

Willinger M, James LS, Catz C. Defining the sudden infant death syndrome (SIDS): deliberations of an expert panel convened by the National Institute of Child Health and Human Development. Pediatr Pathol. 1991;11(5):677-684.


Weese-Mayer DE, Marazita ML, Berry-Kravis EM, Patwari PP. (Updated November 10, 2011). Congenital Central Hypoventilation Syndrome. In: GeneReviews at GeneTests: Medical Genetics Information Resource (database online). Copyright, University of Washington, Seattle. 1997-2012. Available at Accessed July 9, 2012.


First Candle-SIDS Alliance

2105 Laurel Bush Road

Suite 201

Bel Air, MD 21015

Tel: (443)640-1049

Tel: (800)221-7437



National Sudden and Unexpected Infant/Child Death Resource Center

2115 Wisconsin Avenue, NW

Suite 601

Washington, DC 20007

Tel: (202)687-7466

Fax: (202)784-9777

Tel: (866)866-7437



NIH/National Institute of Neurological Disorders and Stroke

P.O. Box 5801

Bethesda, MD 20824

Tel: (301)496-5751

Fax: (301)402-2186

Tel: (800)352-9424

TDD: (301)468-5981


American SIDS Institute

528 Raven Way

Naples, FL 34110


Tel: (239)431-5425

Fax: (239)431-5536

Tel: (800)232-7437



SIDS Educational Services, Inc.

PO Box 2426

Hyattsville, MD 20784-0426

Tel: (301)322-2620

Fax: (301)322-9822



NIH/National Institute of Child Health and Human Development

31 Center Dr

Building 31, Room 2A32


Bethesda, MD 20892

Fax: (866)760-5947

Tel: (800)370-2943

TDD: (888)320-6942



Foundation for the Study of Infant Deaths

11 Belgrave Road

London, SW1V 1RB

United Kingdom

Tel: 02078023200

Fax: 08707870725

Tel: 08707870554



Genetic and Rare Diseases (GARD) Information Center

PO Box 8126

Gaithersburg, MD 20898-8126

Tel: (301)251-4925

Fax: (301)251-4911

Tel: (888)205-2311

TDD: (888)205-3223


Infants Remembered In Silence, Inc. (IRIS)

112 Third Street NE

Faribault, MN 55021

Tel: (507)334-4748

Fax: (507)334-4748



Share Pregnancy & Infant Loss Support, Inc.

402 Jackson Street

Saint Charles, MO 63301

Tel: (636)947-6164

Fax: (636)947-7486

Tel: (800)821-6819



Sudden Infant Death Services of Illinois, Inc.

6010 Route 53

Suite A

Lisle, IL 60532

Tel: (630)305-7300

Fax: (630)305-4773

Tel: (800)432-7437



CJ Foundation for SIDS, Inc.

HUMC: WFAN Pediatric Center

30 Prospect Avenue

Hackensack, NJ 07601

Tel: (551)996-5301

Fax: (551)996-5326

Tel: (888)825-7437



For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see