Blog Post 4.18.15 Overheating and SIDS Part 2

For part 1, click here!


Well, for the better half of Jia’s first year, I was slightly obsessive over taking precautionary measures to minimize Jia’s risk of SIDS (Sudden Infant Death Syndrome). SIDS is the sudden death of an infant less than 1 year of age that occurs during sleep, that is unexplained after investigation through an autopsy. And in 2010, according to the National Vital Statistics System at the Centers for Disease Control and Prevention, SIDS is the #3 leading cause of infant death in the United States. (Congenital malformations (deformations and chromosomal abnormalities) and short gestation/low birth weight were the first and second causes, respectively.)1 (this is the most current death data available)

A triple-risk model (how a combination of 3 contributing risk factors) for SIDS was published in an issue of Pediatrics2, and defined vulnerable infants as the following: 

Image from Trachtenberg et al., Pediatrics; 2012. 129(4): 630-638.

Image from Trachtenberg et al., Pediatrics; 2012. 129(4): 630-638.

As you can see from the image, “genetic polymorphisms” in the “vulnerable infant” category is a harder one to really pinpoint or know unless you had extensive genetic analysis performed or knew that SIDS deaths ran in your family. Babies in the critical developmental period are those infants <1 year, and exogenous stressors are environmental/situational things that can play a role. 

The Back to Sleep/Safe to Sleep Campaign3 reminds us that SIDS is:

  • NOT Death by suffocation
  • NOT caused by vaccines/immunizations/shots
  • NOT caused by vomiting or choking
  • NOT completely preventable (though measures can be taken that greatly reduce the risk)
  • NOT caused by cribs

I studied maternal and child health for years and worked in public health long enough that the “Back to Sleep”/Safe to Sleep Campaign burned a permanent slogan into my head, when it came to the topic of infant sleep. After all, according to a research study by Trachtenberg, et al., the Back to Sleep Campaign, which began in 1994 by the National Institute of Child Health and Human Development, almost immediately and significantly reduced the number of SIDS deaths by more than 50% over the course of 10 years after its inception.2

So obviously, since the arrival of Jia, we had to be sure we were taking all measures to make sure everything was done right.

What We Did

I was adamant that we follow recommendations to prevent SIDS – nothing was in her crib besides her wubbanubb pacifier (no bumpers, no stuffed animals, not even blankets hanging on the siderail), she was swaddled while dressed in a single light layer, was always placed on her back to sleep, and we kept our condo at a cool 68-70 degrees at all times. In my new-mom wave of paranoia, I thought that somehow gravity might yank that baby blanket into the crib area, even if I left it hanging decoratively along the back railing. I was even concerned that even a 12″ lovey may suffocate her if she moved around the crib – the baby that couldn’t lift her head if her life depended on it – so I avoided any of that at all costs. And, while breastfeeding was never a choice made solely to prevent SIDS, we were following that as well. 

Now don’t get me wrong, now that Jia is nearly 14 months old and healthy (very much alive), I’m not regretting being anal-retentive when it came to her safety – even if I may have gone overboard with Hi-Sense under-mattress sensor pad monitoring during all periods of sleep – even during her short naps. Heck, we still put Jia in her trusty Halo Sleepsacks and I’m still too worried about putting a blanket in her crib. I mean, she wouldn’t know to pull it on top of her if she were cold, so why bother with one at all for now, since she rolls all around her crib throughout the night anyway?

So What’s Considered a “Safe Sleeping Environment”?

The following are modifiable risk factors to create a SAFE SLEEPING ENVIRONMENT (for 1st year):3, 4, 5, 6, 7

  • Firm sleep surface, a safety-approved crib mattress that fits the crib, with no more than two-fingers widths of space between the mattress and crib slats.
  • Fitted sheet on the mattress ONLY.
  • No blankets, no stuffed animals, no pillows, no bumpers.
  • No smoking near the baby or even when pregnant.
  • Nothing covers baby’s head during sleep
  • Always place baby on his/her back during all sleep (nap and night sleep).
  • Room-sharing is encouraged in the first year, where baby sleeps in a bedside crib or bassinet (room sharing, NOT bed sharing!!) According to the AAP, this encourages and facilitates breastfeeding and baby monitoring.
  • Baby should NOT sleep in an adult bed (“co-sleeping”), in a chair, on a couch, alone or with you.
  • Keep the room temperature comfortable for an adult, between 68-72 degrees Fahrenheit.8
  • Breastfeed! A meta-analysis of case-controlled studies published by the American Academy of Pediatrics4 found a statistically significant reduction in SIDS by 50% when infants were EXCLUSIVELY breastfed (no formula) for at least 4-6 months and continued through at least the first year of life (longer duration of breastfeeding had an increased protective effect = positive “dose response”). They also found that formula bottle-fed infants had a statistically significant increase in SIDS. This is because: 
    • Breastfed infants are more easily aroused from active sleep during the high-risk SIDS period (first 6 months). This is a good thing, even though it sounds dreadful for new parents.
    • Breastmilk provides immunologic factors that are protective in SIDS, that prevent illness and inflammation that could be associated with babies’ vulnerability to SIDS.
    • The act of breastfeeding is also physiologically calming to babies, so the closeness and benefits of bonding through nursing is able to soothe baby and creates a peaceful sleep/wake cycle.
    • Pediatrician Dr. Sears9 is on-board with my theory about strengthening baby’s sucking reflex: He writes that breastfeeding may strengthen the coordination between sucking, swallowing, and breathing. Formula-fed babies tend to feed less often, since formula moves slower through a baby’s system (they full fuller, longer), so babies who are fed breastmilk require more frequent feedings = more frequent workouts for baby’s throat and airway, leading to stronger muscle support.
  • No positioning devices that claim to reduce the risk of SIDS (like wedge pillows or baby body positioners)
  • Provide plenty of tummy time when baby is awake and when someone is watching. 
  • Avoid overheating:
    • Avoid dressing baby in 2 or more layers when sleeping – this can lead to overheating, which may cause baby to sleep too soundly, unable to wake themselves up. 
    • Sweating, flushed red cheeks, damp hair, heat rash, and rapid breathing are all signs of a baby being too warm. 
    • Research suggests that higher room temperatures contribute to risk of SIDS (since I don’t have permissions, I’m listing the references the NICHD provided below). As mentioned above, keep the room temperature 68-72 degrees Fahrenheit.
  • Provide a pacifier for baby when sleeping (if breastfeeding, offer a pacifier once nursing is well established, after about 1 month). According to a research study published by the AAP, pacifiers may offer protection by providing a space between the infant’s airway and any surface that could block airflow to baby. It can also offer protection by maintaining an open airway through sucking, encouraging forward positioning of the tongue, keeping that back part of the throat (oropharyngeal) open for air flow.10 
  • Provide a electric fan in the room, helping airflow past baby’s nose. This is thought to circulate fresh air and prevent rebreathing exhaled carbon dioxide near their nose.11 

Overheating & SIDS 12, 13, 14

Of all the guidelines to follow to reduce the incidence of SIDS…

the one that wasn’t clear to me was the association between baby being too warm (due to their clothing being too heavy and/or a room temperature above 72 degrees) and SIDS. Also, why is a room fan protective

I’d been given a handout at our childbirth class, published by Halo Sleepsack and the National Sleep Foundation that recommended a room temperature between 68 and 72 degrees#&. But how does that – physiologically – create a safer sleep environment? 

Although much of the research that is conducted on the topic of SIDS-related deaths finds strong associations between the recommendations (obviously that’s why the AAP and NIH develop these recommendations, after all), they really couldn’t determine physiologically WHY. And, while reliable websites like along with other parenting resources do a good job in TELLING the parents what to do and what not to do, many fail to explain why, as well. With such an ambiguous condition (like SIDS) it’s often difficult to define exact causative factors. Researchers work hard at finding the answers for why A causes B, but sometimes it is really hard.

Rather, research is often limited to showing that A causes B, which influences C. 


I looked through various research articles for these answers (sources below) and while it’s hard for even researchers and experts to definitely pinpoint the direct association between recommendations and SIDS, they do, on the other hand, offer hypotheses that illustrate their indirect relationships. 

The hypothesis linking warm room temperatures and overheating to SIDS-related deaths is founded upon the concept of “thermal stress.” This refers to rebreathing of carbon dioxide that is exhaled. We breathe more rapidly and more deeply when we are hot, to cool our bodies down. Same goes for infants.  In times of being over-warm, infants attempt to cool themselves by breathing heavier, thus more carbon dioxide is exhaled and then re-inhaled. Typically if you – an adult – have good air circulation, the CO2 (carbon dioxide) you exhale isn’t a problem since it is circulated through the room and doesn’t stay close to your face. But, for babies, researchers consider their vulnerable age, less mature immune systems, and inability to sense when oxygen and CO2 levels have changed warranting a change in position, to put them at risk.

Thus, SIDS recommendations of providing a room fan11 (to circulate clean fresh oxygen-rich air), placing infants on their backs to sleep (so fresh air bypasses the nose versus lying on their stomachs where exhaled CO2 is not as well circulated), and keeping an infant from becoming overheated pretty much go hand-in-hand.

So What You’re Saying Is…

I know. I’m a little underwhelmed at what I found on this topic, because I was hoping to find this cloud-parting “A-HA!” answer. But, much like SIDS itself, it’s hard to hit the nail on the head with this one. All experts can do is highlight what we should be doing, point us in the right direction, and hopefully we will never have to face the heart-wrenching awful and horrific experience of waking up to find their precious little baby lifeless.

SIDS is real, it’s serious, and the precautions are real as well. While a lot in the field of medicine is known (like the reason someone had a heart attack is because of plaque speckled along the arterial walls to the heart), a lot is hazy at times, as well. Doctors don’t always have the answers – It’s a limitation we deal with in the medical field sometimes – but there are ongoing efforts to fill in the gaps.

So what do you do? Well you try your darnedest to prevent these things from happening, with whatever answers researchers have found thus far. 

Just remember, according to the Safe to Sleep website#!, 90% of SIDS deaths occur in infants 1 to 6 months of age, with peaks between months 1 and 4. The risk is still present throughout the entire first year of life, so precautions should be followed until baby’s 1st birthday.

Sources/Additional References: 

1.  NVSS- Death Data 2010:

2. Risk Factor Changes for Sudden Infant Death Syndrome After Initiation of Back-to-Sleep Campaign. Trachtenberg F., et al. Pediatrics, 2012. 129(4): 630-638.

3. National Institutes of Health National Institute of Child Health and Development: Safe to Sleep –

4. Breastfeeding and Reduced Risk of Sudden Infant Death Syndrome. Hack F., Thompson J., Tanabe K., Moon R., Vennemann M. Pediatrics, 2011; 128(1): 103-110.

5. (I didn’t have access to the original article that was referenced)

6. Research on overheating, room temperature, and its association with SIDS:

  1. Fleming, P. J., Gilbert, R., & Azaz, Y. (1990). Interaction between bedding and sleeping position in the sudden infant death syndrome: A population-based case-control study. British Medical Journal, 301, 85-89.
  2. Gilbert, R., Rudd, P., & Berry, P. J. (1992). Combined effect of infection and heavy wrapping on the risk of sudden unexpected infant death. Archives of Disease in Childhood, 67, 171-177.
  3. Ponsonby, A. L., Dwyer, T., Gibbons, L., Cochrane, J. A., Jones, M. E., & McCall, M. J. (1992). Thermal environment and SIDS: Case-control study. British Medical Journal, 304, 277-282.
  4. Ponsonby, A.L., Dwyer, T., Gibbons, L. E., Cochrane, J. A., & Wang, Y. G. (1993). Factors potentiating the risk of sudden infant death syndrome associated with prone position. New England Journal of Medicine, 329, 377-382.
  5. Williams, S. M., Taylor, B. J., & Mitchell, E. A. (1996). Sudden infant death syndrome: Insulation from bedding and clothing and its effect modifiers. International Journal of Epidemiology, 25, 277-282.

7. SIDS and other sleep-related Infant Deaths: Expansion of Recommendations for a Safe Sleep Environment. Task Force on Sudden Infant Death Syndrome. Pediatrics, 2011; 128: 1030-1039.

8. Halo Sleepsack: Tips on Safe Sleep for Baby:

9. Dr. Sears: 8 Reasons Breastfeeding Reduces SIDS:

10. Do Pacifiers Reduce the Risk of Sudden Infant Death Syndrome? A Meta Analysis. Hauck F., Omojokun O., Siadaty M. Pediatrics. 2005; 116(5)e716-e723.

11. Use of a Fan during Sleep and the Risk of Sudden Infant Death Syndrome. Coleman-Fox K., Odouli R., Li D. Archives of Pediatrics and Adolescent Medicine. 2008; 162(10): 963-968.


13. Ambient Heat and Sudden Infant Death: A Case-Crossover Study Spanning 30 Years in Montreal, Canada. Auger N., et al. 2015, Environmental Health Perspectives for Advanced Publication from the National Library of Medicine:

14. Interaction Between Bedding and Sleeping Position in the Sudden Infant Death Syndrome: A population-based case control study.

More of the Facts (info obtained from the National Institutes of Child Health and Human Development)