Sudden Infant Death Syndrome (SIDS): What You Need to Know

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It’s not something we want to think about, or even talk about for that matter. As parents, it’s our greatest fear; sudden and unexpected death of an infant. It’s a devastating and shocking occurrence, and it’s essential that we are up to date with current information and recommendations surrounding SUID/SIDS (Sudden Unexpected Infant Death/Sudden Infant Death Syndrome).

Today there is so much more information, more than ever before. There are a lot of advice on parenting left, right and center, some of it unsolicited and unwanted. With so much information and so many different types of parenting styles, it can be confusing to wade through all the various recommendations.

A lot of changes happened as there is so much new research and medical studies since our parents were parents with a baby. Grandma and grandad’s advice is not always the best. Being informed as possible in regards to the safety of our babies is an advantage.



It’s gotten a little confusing in the past few years with different acronyms and different definitions to describe the sudden or unexpected death of an infant. It was during the 1950s that  SIDS (Sudden Infant Death Syndrome) became medically accepted. Now, we use the term SUID as an umbrella term.

According to the Centre for Disease Control and Prevention, “SUID (Sudden Unexpected Infant Death) is used as a wide term that encompasses all sudden infant deaths. It would include SIDS (Sudden Infant Death Syndrome), accidental deaths (such as suffocation and strangulation), sudden natural death (such as those caused from infection, cardiac or metabolic disorder, and neurological conditions), and homicides.”

Approximately 3,500 babies die every year in the US from SUID, with the most common causes being SIDS, unknown causes and accidental suffocation or strangulation in bed. The percentages below have been sourced from the Centre for Disease Control and Prevention from data recorded in 2016.

Over the last 70 years, more information and data has been collected to understand SUID and help to inform parents of safe sleeping practices to help protect our children.  Safe sleeping practices so important as the majority of SIDS deaths occur while the infant is sleeping.

Understanding SIDS

SIDS being the leading cause of death under the SUID umbrella, we need to understand what we can do to minimize the danger to our infants. Currently, the understanding of SIDS revolves around a theory called the Triple Risk Model.

The Triple Risk Model suggests that there have to be three factors present for SIDS occurs. These three factors are The Critical Development Period (0-6 months), a vulnerable infant, and outside stresses. The current understanding is that for SIDS to occur all three of these factors needs to be present. These explain why some infants are ok when exposed to outsides stressors and some are not.

The Critical Development Period

SIDS can occur at any moment during the first year of an infant’s life. However, 90% of cases occur in the first six months of life, with 70% occurring between the ages of 2-4 months. It is the reason is why 0 to 6 months is considered a time of critical development as this is the age when an infant is most susceptible to SIDS.

There is nothing we can do about this factor, except be aware and extra vigilant with safety. Our baby is going to grow and develop whatever we do.  But we can be attentive with our safety during this time and make sure we are not exposing our baby to any outside stressors.

A Vulnerable Infant

A vulnerable infant is a baby that has an underlying weakness or vulnerability that may or may we may not be aware. We may know if our baby is considered a vulnerable infant, but we also may not.

These can be babies who were born prematurely, with low birth weight, exposed to drugs, alcohol, or cigarette smoke while in the womb. However, it is possible to have an underlying vulnerability that is currently undetectable.

At present scientists are finding that a large percentage of babies who die from SIDS have had a brain abnormality. It’s believed that this brain abnormality occurs in the brain stem where waking from sleep, breathing, temperature, blood pressure, and heart rate controls are found. This defect can cause the infant to be considered a vulnerable infant.

Infants with this condition may not be able to cope with outside stressors as much as a baby who is not in the same state.  At this stage, there is still no way to identify if a baby is vulnerable or not.

There is also research and development into genetic factors which may increase the vulnerability of an infant and increase their risk of succumbing to SIDS.  At present we do not know which babies may suffer from this abnormality or genetic variance.

With more research, hopes got high that these infants will be able to be identified in the future to reduce the risk of SIDS further.

Outside Stressors

Outside stressors are the most critical factor, as this one is mostly within our control. External stressors are tummy sleeping, sleeping on a soft surface, pillows, bed sharing, second-hand smoke, overheating, and respiratory infections.

A baby who is not a vulnerable infant may be able to survive these outside stresses, but those that are, cannot. The reduction of external stressors is the most valuable way that parents can work to reduce the risk of SIDS.

It is currently thought that for SIDS to occur all three of these factors need to be present.  It’s also believed the amount of stress an infant incurs needs to match the level of vulnerability they have.  It means that we cannot know which stressors or how many stress might tip the scale towards a case of SIDS and why some babies are ok, and some are not.

The thing is that we are not aware and we need to minimize as much risk as possible.   With current information around SIDS and the Triple Risk Model the best thing we can do is treat all infants as vulnerable infants, be aware of the risk from 0 to 12 months,  being especially vigilant during the first 6 months of life, and not place any outside stressors or environmental challenges on our babies while they are sleeping.


Reduce the Risk of SIDS – Guidelines Sourced from the American Academy of Paediatrics (AAP)

The AAP is an organization of 67,000 pediatricians who are committed to the health and wellbeing of children. They provide professional resources, education, policies and information to ensure optimal health for children.

1. Back to Sleep

One of the most vital steps towards safe sleeping for your baby is to place your child to sleep on their back. This sleeping position has been proven to be the most reliable way for infants to relax and helps enormously to reduce the risk of SIDS.

During the ’90s a ‘Back to Sleep’ campaign was launched to educate parents on the safety of a back sleeping position. There was a 50% drop in infant death over the years.  This has been an incredibly successful campaign with the lives of many babies saved through one simple step.

For parents worried about the safety of back sleeping, the AAP has found through research and studies that back sleeping does not cause choking or aspirations, (Aspiration is when a foreign body such as food or saliva enters the lungs) even if your baby suffers from reflux.

The APP recommends placing your baby to sleep on their back until they are 12 months old. When your baby can roll successfully from back to tummy and back again they can stay in whatever sleeping position they assume.

However, you should still place your baby to sleep on their back until they are 12 months old.  Back sleeping is the most significant and vital step that you can take towards safe sleeping.

Why are tummy and side sleeping dangerous?

Tummy time is great when a baby is awake and observed by their caregiver.  Awake tummy time is essential to strengthen neck and shoulder muscles, prevent flat spots occurring on your baby’s head and increasing their gross motor skills.

Babies should not be placed on their tummy to sleep as in this position babies are more likely to overheat, rebreathe expelled air which leads to a buildup of carbon dioxide and obstruction of the babies upper airways.

There has been an established link between tummy sleeping and SIDS.  Tummy and side sleeping is an outside stressor for a baby and is a no-no when putting a baby down for sleep.

2. Where Should My Baby Sleep?

As babies are considered to be in the critical development period from 0 to 6 month, with the majority of SIDS cases occurring during this time, a good recommendation would be to sleep in your room on a separate surface for the 1st year of life, or at least six months.

Sleeping in the same room as parents have shown to be very beneficial to mothers and children.  Room sharing also decreases the risk of SIDS by up to 50%. Room sharing allows parents to comfort, feed easily and be aware of their baby needs during the night and naps.

Another recommendation is that when feeding in bed infants should be returned to their sleeping device when finished. If the parent falls asleep while feeding, they can transfer the baby back to their crib when they wake up. Parents should never sleep with the baby on couches and armchairs as they can be dangerous places for infants to sleep as suffocation and entrapment can quickly occur.

It is not advisable to place your baby on a couch or armchair to sleep. These sleeping surfaces create risky sleeping surfaces for babies.  It is easy for a baby to suffer from entrapment or suffocation on these surfaces.

The AAP is aware that parents often fall asleep while feeding their baby. They recommend the parents be extra vigilant when feeding on a couch or armchair.  Once the infant is asleep, it is a must they sleep on their back on a firm surface as soon as possible.

3. Sleeping Environment

All soft objects such as pillows, toys, blankets, and bedding should be kept clear of your baby's crib to prevent suffocation or entrapment. All your baby needs is a tightly fitted sheet.  It is preferable to clothe infants in wearable blankets or swaddles. Bumper pads are also not recommended for the same reason as they can cause suffocation. Suggestively, your baby needs one more layer than you do to feel comfortable.

What should my baby sleep on?

a. Sleeping Device

Your baby should only sleep on a firm surface approved for safe sleep. You can add a fitted sheet and no other loose bedding, cushions or blankets. The area should be free and clear.

b. Falling Asleep in Places other than the Crib

Swings, prams, car seat, baby carriers should not be used for routine sleep. But if your baby does fall asleep in a pram or car seat make sure baby's airways are transparent, free and their position is safe.

If you are home, you should move your baby from the device and into their crib as soon as possible. These devices can be particularly dangerous for babies under four months of age as they may easily fall into a position that could obstruct their airways or cause asphyxiation.

You should never leave your baby unattended if they are asleep in any device such as a car seat or swing, and they should be moved to a crib as soon as possible.  There should be no devices placed on the crib mattress.

c. Bedside Sleepers

It is a bit of a shady area. There are currently no safety recommendations for bedside sleepers.  To date, studies are still not available for these products and associations with SIDS.

Nowadays, there are no safety recommendations for in bed sleepers either.  However, the APP guidelines are particular in regards to the best sleeping surfaces for infants, and its best to address these. They recommend a firm and separate sleeping surface.

d. Carrier and Slings

If you are using a carrier or sling to carry your baby make sure their head is up and free and clear of any fabric.



Although swaddling is an excellent sleep aid for babies, it does not reduce the risk of SIDS. It is used to calm babies. Swaddled babies should not be placed on their tummy to sleep as this increases the risk of SIDS.

When wrapping the fabric should be firm around the arms and chest and loose around the hips and legs to allows movement and avoid problems with hip dysplasia. When your baby is starting to roll it is an excellent time to stop swaddling, so they do not end up wrapped and sleeping on their tummy.

Co-Sleeping/Room Sharing/Bed-Sharing

Co-sleeping is sleeping close to your baby. The AAP recommends room sharing for at least the first six months of your baby’s life to decrease the risk of SIDS and ideally 12 months. They do not recommend bed-sharing. Although bed-sharing may be a common occurrence for some families, professionals do not recommend it as there are so many outside stressors added in this type of sleeping environment.

The AAP especially recommends not bedsharing when:  

  • The baby is younger than 4 months of age
  • The baby was born prematurely or had a very low birth weight
  • A parent smokes, even if they do not smoke in bed
  • A person who may be under the influence of medication, is heavily fatigued, or has used alcohol or illicit drugs
  • When sleeping on a couch, armchair, waterbed, sofa
  • When sleeping with lots of bedding and bed accessories

Room sharing without bed-sharing has been demonstrated to provide all the benefits of co-sleeping without the risk of entrapment or strangulation.  As there have been no significant studies to date which ascertain whether these devices are safe or reduce the risk of SIDS, avoiding devices which claim to make bed-sharing safe is a must.

Food and Safe Sleeping

Breastfeeding is recommended; mums should try to breastfeed exclusively for six months. However, any breastfeeding is still more protective than not breastfeeding at all.

Breast milk is beneficial in helping to reduce SIDS for a variety of reasons including:

  • Helps infants to fight infections   

A baby is still developing their immune system and their body cannot fight infection as quickly or as efficiently as their mother's body can.  While they were in the womb babies had all the benefits of their mother's immunity.

Now their outside in the world and a mothers breast milk carries many antibodies that their baby might need to fight infection that their bodies are not currently able to make.

Breast milk is kinder to babies airways and they are not exposed to any allergens.  Also if breastmilk accidently swallowed to the lungs it is less of an irritant

  1. Breast milk can help to reduce reflux
  2. Breastfeeding increases a mothers awareness of her baby
  3. Breastfeeding helps to improve swallowing and breathing coordination in babies

However, I appreciate that not all mothers can breastfeed for a variety of reasons. Not all can breastfeed exclusively for six months.  Talk to your doctor, pediatrician or lactation consultant if you are concerned about breastfeeding or looking to stop. You need to work out the healthiest feeding solution for baby and yourself.

What about dummies/pacifiers?

Studies have shown the use of a dummy/pacifier reduces the risk of SIDS. Although, professionals do not know why. Using dummies still reduces the risk of SIDS even if it falls out of the baby's mouth while they are sleeping.

Only use the pacifiers when placing your baby to sleep. If your baby refuses to take it, don't force them but retry from time to time. It should not be hung around the neck or attached to their clothing. It's best to introduce pacifiers once breastfeeding started.

Other Risk Factors

  • Smoking during or after pregnancy. Also being around people who smoke while pregnant.
  • Alcohol and illicit drugs during and after pregnancy
  • Overheating and head covering.
  • Commercial devices that claim to reduce SIDS.
  • Bed sharing with infants 0-4 months, also preterm and low birth weight infants.
  • Also, bed sharing with a smoker even if they do not smoke in the bed.
  • Bed sharing with someone affected by a substance, alcohol, drugs, or certain medicines.
  • In addition, bed sharing with someone who is not the baby's parent.
  • Bed sharing on a soft surface and bed sharing with soft bedding accessories.


There is no evidence found on the link between immunizations and SIDS. Most recent information shows that vaccines can be protective against SIDS.

The best defense we as parents have against SIDS is education and acting on the best and most current information. Yes, your mum may have tummy slept you and your brothers and sisters. Your friends may bed-share. Maybe you know someone who swears by covering their baby in lots of blankets.

They may not have had a vulnerable infant. We don’t know which babies are vulnerable infants at this stage. The best steps we can take for safe sleeping practices is to reduce all many stressors in our babies sleep environment as possible.

The AAP has committed to the health and wellbeing of babies. They conduct numerous studies and research into the guidelines and recommendations. You can view their document here.

If you have any concerns about products or the sleeping environment of your baby, you should contact your GP or pediatrician.

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