Everything You Need to Know About SIDS

If you’re expecting a baby and are concerned about sudden infant death syndrome (SIDS), you’re certainly not alone. SIDS ranks very high on the list of anxiety-inducing topics for new parents. Thankfully, researchers have identified a number of simple measures you can take to protect your baby. Let’s take a look at those findings and equip you with the knowledge to keep SIDS at bay.

What Is SIDS?

Sudden infant death syndrome, or SIDS, is also sometimes called “crib death” because it generally happens while the baby is asleep. SIDS is generally defined as the sudden and unexpected death of an infant under 12 months of age that remains unexplained after a review of the clinical history, complete autopsy and death scene investigations. 

SIDS is a subset of a broader category of infant deaths called sudden unexpected infant death (SUID). Babies who die suddenly and unexpectedly of causes that are later explained (abnormalities, infections, etc.) fall under the SUID category. The lack of an explainable cause of death sets SIDS apart from other types of SUID.

The Triple-Risk Model

Researchers are still trying to determine what causes SIDS, but for now that remains a mystery. One tool they use to try to understand SIDS deaths is the Triple-Risk Model. As the name implies, this model looks at three categories of risks:

  1. Vulnerable infant: This could be an underlying brain abnormality in the areas of the brain that controls breathing or the heart. Certain genetic mutations could also be considered here.
  2. Critical developmental period: Rapid growth creates many important changes during a baby’s first 6 months of life. Some of these can temporarily destabilize the baby’s internal systems.
  3. Outside stressors: These are the risk factors we will discuss below: stomach sleeping, overheating, second-hand smoke, etc. While these may not be critical on their own, a vulnerable infant may not be able to overcome them.

Researchers believe that babies are at very high risk of SIDS when all three of these sources of risk are present at the same time.

SIDS Triple-Risk Model

How Common Is SIDS?

In the United States, and in most of the Western world, SIDS is the leading cause of mortality for babies between 1 month and 1 year of age. Most deaths due to SIDS happen between 1 and 4 months of age and 90% happen before 6 months of age. This is why co-sleeping for the first 6 months is so important, as we will further discuss later.

The good news regarding SIDS is that incidences have dramatically decreased since the early 90’s. This is no coincidence as 1992 marked the launch of the American Academy of Pediatrics’ (AAP) safe sleep program and 1994 was the year the National Institute of Child Health and Human Development (NICHD) launched the Safe to Sleep campaign (previously known as Back to Sleep). As a result, the SIDS rate in the United States declined from 130.3 deaths per 100,000 live births in 1990 to 35.2 deaths over 100,000 live births in 2018. In terms of total deaths, this represents a drop from 5,417 in 1990 to 1,300 in 2018. These two programs aimed to spread information regarding risk factors for infant death and ways for parents to help prevent them.

Main Risk Factors for SIDS

Research has demonstrated several factors that can put babies at higher risk for SIDS and other sleep-related causes of infant death:

Stomach or side sleeping: Babies sleeping on their sides are more likely to end up on their stomach, and babies sleeping on their stomach are at a higher risk of suffocation. Infants might not yet have developed the reflex to turn their head when they are unable to breathe properly.

Sleeping on soft surfaces, such as an adult mattress, or in a crib with loose bedding: Once your baby can roll over on their own, usually at around 6 months of age, they may find themselves sleeping on their stomach. Sleeping face down on something soft can block your baby’s airways and lead to suffocation. 

Overheating: Infants can’t properly regulate their body’s temperature and are thus sensitive to extreme temperatures. According to the NIH, studies have shown that warm blankets or clothing and warm room temperatures increase the risk of SIDS.

Being exposed to cigarette smoke in the womb or in their environment after birth: According to the CDC, smoking during pregnancy increases the risk for SIDS. Infants who are exposed to second-hand smoke are also at greater risk for SIDS. This appear to be due to the chemicals in second-hand smoke which interfere with the brains ability to regulate breathing.

Sharing a bed: It’s dangerous for an infant to sleep with an adult (or another child) in an adult bed or on a chair/couch as it increases the risk of suffocation.

Pre-term births:  According to a 2017 study published by Rutgers University, premature babies have a greater risk of SIDS compared to full-term babies. If you give birth before term, it is even more important that you avoid the risks we just discussed to provide your little one with safe sleeping conditions.


We noted earlier that the Safe to Sleep campaign led to a huge reduction of SIDS in the United States. So, what tips does it provide to help parents prevent SIDS?

Place baby on their back: This is the safest position for babies until they are at least 1 year old. There is no need to reposition babies if they roll over on their own, the key is to start them on their back. Please note – this is very important – that babies used to sleeping on their back are at very high risk of SIDS if they are then placed on their stomach. This means that it is extremely important to educate anyone who might look after your little one to ensure they put them to sleep on their back.

Use a well-fitted, firm mattress in a safety-approved crib, covered by a fitting sheet only: Despite the marketing images showing cribs with all kinds of soft things in them, that is not how cribs are meant to be used for infants. It is absolutely crucial that the crib contains nothing but the fitted sheet covering the mattress. This means no pillow, bumper pads, blankets, stuffed animals, etc. 

You should also ensure that your crib (or bassinet) is compliant with CPSC’s most recent standards (all cribs sold in the US after 2011 should be, by law) and that your mattress is firm or ultra-firm and well-fitted to your crib (dimensions can vary a little). Finally, your baby should not be left to sleep for extended periods of time in car seats, strollers, swings, etc.

Breastfeeding: Babies who are exclusively breastfed (or fed breastmilk) have been shown to be at lower risk for SIDS than babies who do not breastfeed. It’s important to try to stay awake during breastfeeding at night and to put baby back in their sleeping area (crib or bassinet) when finished.

Co-sleeping: Sharing a room with your baby reduces the risk of SIDS. It is recommended to co-sleep for at least the first 6 months but preferably for the first year. It is worth repeating that baby should be sleeping in their own sleeping area (crib or bassinet) and not sharing a sleep surface with you.  This is to reduce the risk of suffocation. When breastfeeding or comforting your baby, avoid falling asleep with them in your arms.

Mommy care: To reduce the risk of SIDS, moms should take care of their own bodies. Prior to birth, moms should receive regular prenatal care. Additionally, moms should avoid smoking, drinking alcohol, and using marijuana or other drugs during pregnancy as well as after birth.

Pacifiers: The use of pacifiers has been demonstrated to reduce the risk of SIDS. Make sure that there is nothing attached to the pacifier as this could pose a suffocation risk (think strings, stuffed toys, etc.).

Do not let baby overheat during sleep: Babies should be dressed appropriately for the environment and use sleep clothing such as a wearable blanket. However, they should never be over-bundled or over dressed for the temperature inside their room. Parents should look out for signs of overheating such as sweating or the baby’s chest feeling hot to the touch. As previously discussed, infants do not possess the ability to adequately regulate their body’s temperature.

Ensure your baby gets plenty of tummy time: Tummy time strengthens your baby’s neck and upper body muscles and improves their motor skills, all of which reduces the risk of SIDS. It also has the added benefit of preventing flat spots on the back of your baby’s head.

Avoid products that go against the Safe to Sleep guidelines: As noted by Safe to Sleep, there are no known ways to prevent SIDS. As such, any product advertised as reducing SIDS is being falsely marketed and, in some instances, could pose a hazard to your baby.

In Conclusion

While the scientific community still does not fully understand SIDS, the reduction in cases in recent years is encouraging. We know as parents that there are very clear steps we can take to minimize the risk of SIDS in our babies. By avoiding all key risk factors and implementing the preventative measures we just discussed, you can give your baby the best possible chance of avoiding SIDS.

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