Sudden Infant Death Syndrome (SIDS) – What is it?

Why you need to know about SIDS

People who don’t have children are probably aware of Sudden Infant Death Syndrome (SIDS), but they don’t get into the details all that much.  Why should they?  Then, the day arrives when they are happily planning for the arrival of a bundle of joy, and, all at once, like miserable pessimists, their doctor and other healthcare workers start warning them about it, over and over again.

And, even after their beautiful child is in their arms, those same people keep on warning them, over and over again.  They even hand them pamphlets about it, filled with scary stories and dire warnings from the medical community.

Then, there are lots of other people, experts, people who call themselves experts, and even relatives and friends who insist they know better and demand that you practice certain routines and/or do things a particular way in order in order to prevent SIDS (and practically everything else for that matter), like breast feed or use formula, sleep in a crib or co-sleep, etc.

For many, all this advice and persistence just gives parents anxiety, confusion and even more fear.  And, parents already have enough to stress over and figure out, especially new ones.

Learn and educate yourself about SIDS

A September 26, 2016 article in Psychology Today, entitled Fear of Sudden Infant Death, by Fredric Neuman, M.D., presented a mother of a one-month old who couldn’t sleep since she gave birth due to her worry over SIDS.  She was repeatedly awakening through the night just to check on her infant daughter, and though her daughter was all right each time, her anxiety never diminished.

Dr. Neuman advised the mother to completely educate herself about SIDS, even if some of what she learned was frightening.  He stated that while such may initially frighten her more, confronting her fears would eventually lessen them and allow realistic solutions.  Shortly thereafter, the mother’s anxieties about SIDS stopped altogether.

The aim of this article is to offer a comprehensive understanding of SIDS and present recommendations from the medical community to all, especially expectant parents and new parents.  Some of the details may be frightening, but it is intended to lessen those fears and provide a range of solutions.  As for all situations, not just for parenting, “knowledge is power.”  (Francis Bacon)


Sudden Unexpected Infant Death

When an infant under the age of one dies suddenly, unexpectedly, and without an apparent reason, it is referred to as Sudden Unexpected Infant Death (SUID).  This typically occusr when the child is sleeping and usually no one witnessed what happened.

In 2014, there were about 3.9 million births. Each year there are about 3,500 SUIDs, which equals a rate of .09% SUIDs per year.

Until the 1940s, authorities assumed what they called at the time “crib death” resulted from child abuse, accidental suffocation, or infantile pneumonia.  By the 1970s, medical periodicals and professional associations advised physicians that SUID was probably caused by an unknown mysterious illness or respiratory defect in the brain or respiratory system.


Many states have specific SUID laws. While they vary, each generally calls for a forensic pathologist (county coroner, medical examiner) to conduct an autopsy, an investigation of the scene, a review the child’s medical records, a family assessment, and social services evaluation, if applicable.

The investigation may reveal that the child suffocated because she was trapped between a mattress and a bed frame, because a soft pillow covered her nose and throat, or because a person rolled on top of her while sleeping beside her.  Or, findings may indicate that she was strangled when her head and neck become caught between crib railings. Read our guide about how to choose the right crib and mattress for your baby here.

Death could have also resulted from trauma, a metabolic disorder, hyper or hypothermia, or some other undiagnosed illness. Sadly, too, some deaths are also ruled as homicides.  Regardless, in these circumstances, a particular cause of death was eventually identified.

As mentioned, each state’s laws and regulations varied with regard to investigations of SUIDs.  For example, in Alabama, the medical examiner must cooperate and assist law enforcement with the death investigation and in Maryland, there is a Child Fatality Review Team. In Arizona, the state department of health services sets protocols for infant autopsies, while in New Jersey, the Commissioner of Health and Senior Services sets the protocols along with the medical examiner.  And, these are simply a few examples.

The nationwide inconsistency results in conclusions, rates, and statistics that vary geographically, rather than by medical science.  One state may classify a particular death as asphyxiation, while another state in the same circumstance would call it something different. These conclusions are extremely important because they form the guidelines for determining Sudden Infant Death Syndrome.


What is Sudden Infant Death Syndrome

In some cases of SUID, despite a thorough autopsy and complete investigation, no cause of death can be determined.  This is when investigators and medical examiners can consider Sudden Infant Death Syndrome (SIDS).

The term SIDS was first used in 1969 at an international conference on sudden infant deaths in Seattle.  It has various definitions depending upon the source.  The CDC defines SIDS as: the sudden death of an infant who is less than one year of age that cannot be explained even after a thorough investigation is conducted, including a complete autopsy, examination of the death scene and review of the clinical history.

The Mayo Clinic defines it as:  the unexplained death, usually during sleep, of a seemingly healthy baby who is less than a year old. SIDS is sometimes also known as crib death because the infants often die in their cribs.

Different states different definitions

Some states even have their own definitions.  Utah defines it as: the death of a child who was thought to be in good health, or whose terminal illness has appeared to be so mild that the possibility of a fatal outcome was not anticipated.

Nebraska defines it as:  the sudden, unexpected death of an apparently healthy infant less than one year of age that remains unexplained even after the performance of a complete postmortem investigation, including an autopsy, an examination of the actual scene of death, and also a review of the medical history.

And, Virginia defines it as: a diagnosis of exclusion, the sudden and unexpected death of an infant who is less than eighteen months of age whose death remains unexplained after a thorough postmortem examination which includes an autopsy.

While each defines it a bit differently, Virginia basically pointed out its crux.  SIDS as a formal cause of death is really a conclusion based upon elimination.  In other words, all other causes were excluded and no reason can be identified.

SIDS rate in Mississippi was 12 times higher than in New York

As noted earlier and above, nationwide inconsistencies regarding investigations and definitions have resulted in fluctuating statistics.  Scripps Howard News Services (Scripps) examined official reports regarding the deaths of 40,000 infants who died between the years of 1992 (the most recent year full records were available) and 2007 and noted that the SIDS rate in Mississippi was twelve times higher than in New York.

Other findings revealed that states with review boards assigned to investigate SUIDs were three times more likely to assign suffocation or smothering than were states without such a board; states with well-educated, appointed medical examiners had ten percent higher SIDS findings than states without a similar medical examiner (as some states have corners than aren’t even required to have college degrees).

For those states where the coroner was not required to have a college degree, an “undetermined” cause was 37% higher; and, deaths classified as SIDS were actually due to suffocation in unsafe sleep conditions.


Attempts to unify Investigations of SUID and Diagnoses of SIDS

In 1992, the United States Congress recommended in that the Department of Health and Human Services Interagency Panel on Sudden Infant Death Syndrome create a standard investigation procedure for those who probe SUIDs, including medical examiners, coroners, death investigators, and police officers. The autopsy rate at the time for SUIDs was about 90% and only four states had written guidelines.

Workshops conducted in July 1993 distributed both a standardized short-form and long-form protocols with which investigators could use when investigating SUIDs.  They, however, could not be legislated nationwide and only four states adopted them voluntarily.

In 1996, the Centers for Disease Control (CDC), a federal agency under the Department of Health and Human Services, released its own reporting form (SUIDIRF) regarding SUID investigations, however, assessments were poor. The CDC revised it and released an updated form in 2006, along with manuals for both investigators and trainers of investigators. Both of which were updated in 2014.

It also has training academies in Boston, Atlanta, St. Louis, Albuquerque, and Seattle at which anyone who investigates SUIDs can receive instruction, as well as a Case Registry, which provides detailed data about infant death investigations.

On December 18, 2014, President Barak Obama signed The Sudden Unexpected Death Data Enhancement and Awareness Act. This increased awareness about SUIDs, provided for consistent data collection related to stillbirths and SIDS, and offered information for investigators.

The U.S. Department of Health and Human Services, however, cannot authorize states to mandate SIDS prevention measures.  One of its goals, nonetheless, is to regulate and improve SUID investigations.


Why Standard Protocols are Important

Before Mississippi issued laws ordering coroners to conduct death scene investigations of SUIDs, SIDS determinations surged from 54 in 1994 to 94 in 2002, a 75% increase.  And, this is just one state.  Uniform protocols can:

  • Create one, sensible theory for the reason, method, and mechanism of death;
  • Provide a better grasp of SUIDs and to develop pre-emptive measures;
  • Dispense advice on SUIDs to physicians, healthcare workers, and organizations with child welfare concerns;
  • Assist the coroner or medical examiner in ruling out or ruling in child abuse or neglect, natural causes of death, or trauma; and,
  • Recognize public health hazards, such as those linked to consumer merchandise or unsafe health practices.


Of course the significance of proper investigation is clear for the above purposes and where child abuse and homicide are suspected.  It is still extremely important when it comes to SIDS. One of the other CDC goals in establishing uniform protocols is to support consistent classification and reporting of findings.  Such can:

  • Contribute to the basis of and risk factors for SIDS and to develop preventive procedures;
  • Provide parents and caregivers information about support groups, grief counseling, and healthy infant-care practices; and,
  • Offer information on SIDS to physicians, healthcare workers, specialists and associations that focus on infants.


The significance of these goals when it comes to SIDS cannot be repeated enough.  Such documentation led to the recommendations to reduce the incidence of SIDS.  For example, in 1992, it was discovered that baby sleeping positions were a contributing factor.  70% of infants categorized as SIDS were discovered sleeping on their stomachs.  Such led to the 1994 “Back to Sleep” (BTS) campaign and by 2008, the percentage had dropped to 14.5% (as some parents and childcare providers were still placing baby sleeping face down despite recommendations).


How to Prevent SIDS

prevent sudden infant death syndromeNinety percent of SIDS cases mostly take place before an infant is six months old, yet it can occur at anytime during the first year.  It is the number one cause of death among infants one month to one-year-old in the U.S.  In 2014, there were about 3.9 million births in the U.S. That same year, there were about 1,500 cases of SIDS, which equals a rate of .04%.

While there is no recognized way to completely prevent SIDS, there are recognized approaches that reduce the risk.  And, it begins with pregnancy.  The American Academy of Pediatrics (AAP) recommends that pregnant women refrain from smoking, drinking alcohol, and using drugs and to stay away from smokers and places where people smoke.

Most importantly, always place infants on their backs for every sleep. This must remain a consistent rule until babies reach one year of age.  If, however, she rolls onto her stomach on her own, she can remain in that position.

Safety in the cribs

The AAP also recommends that all soft objects that could increase the threat strangulation, entrapment or asphyxiation out of the crib. Said objects include quilts, pillows, comforters, bumper pads, sheepskins, and stuffed playthings.  While the AAP maintains there is no time when it is 100% safe to have these objects in the crib, most experts agree that they appear little risk to healthy babies older than one year of age.

The AAP advocates that infants be placed on firm sleeping surfaces and stresses that all cribs, portable cribs, bassinets, and play yards should be up-to-date with safety standards and not have broken or missing parts. Never put sleeping babies on a sofa, chair, cushion, waterbed, or sheepskin.

Infants can be placed in the room parent’s also sleep, but the AAP advocates that the child sleep in a bassinet or crib or bassinet, rather than in the same as the parents.  Co-sleeping babies are at an increased risk of SIDS, strangulation, suffocation, and of getting tangled in the sheets or blankets.  Parents could also roll on top of babies while sleeping.

Healthy lifestyle and well baby visits

The AAP also recommends breastfeeding as long possible and as much as possible. Also, ensure strict appearance at all well child visits in order to receive vital immunizations.  As well, if parents smoke, the AAP recommends they stop and/or keep the home, car, and all areas smoke-free and also keep infants away from other smokers and areas people smoke, even outdoor areas.

Set the temperature in baby’s room on a comfortable level and use clothing to keep her warm, rather than blankets.  Offer pacifiers during naps and bedtime.  A baby sleeping with pacifier reduced the threat of SIDS.

Home cardiorespiratory monitors are helpful for infants with breathing or heart problem, but have not been found to reduce SIDS.  Neither are items such as unique mattresses,  wedges, positioners, nor specialized sleeping surfaces.  Infants have actually suffocated utilizing these items.

And, whenever baby is awake, give her adequate of “tummy time,” which strengthens the muscles in the neck and prevents flat spots that might appear on the head.

The AAP recommendations can be found at:


Co-sleeping and SIDS

This remains a sticky subject as some parenting professionals, journals, and other advocates recommend co-sleeping.  Dr. Sears, in two of his books, The Baby Sleep Book and SIDS: A Parent’s Guide to Understanding and Preventing Sudden Infant Death Syndrome, concluded that co-sleeping is safe and actually reduces the risk of SIDS.  There are also other Internet sites that also dispute co-sleeping as a risk for SIDS.

As stated earlier, the American Academy of Pediatrics recommends that parents not co-sleep with their infants. The Mayo Clinic, Science Daily, the Journal of Pediatrics, and the CDC advise the same.




Sudden Infant Death Syndrome (SIDS), Mayo Clinic, June 11, 2016


Brain Abnormality Found In Group Of SIDS Cases, National Institutes of Health, November 24, 2014


About SIDS and Safe Infant Sleep, Safe to Sleep, October 29, 2015


Sudden Unexpected Infant Death and Sudden Infant Death Syndrome, Centers for Disease Control and Prevention, Data and Statistics, February 8, 2016




Anna C

Anna is the main author of this website. Like many of you, she is a mother who is continuously searching for the best parenting tips in order to learn more about child development.