A new article in Pediatrics[1] has been making the rounds as the authors make the suggestion that the American Academy of Pediatrics’ recommendation that all babies room-share for the first year of life to reduce SIDS is unfounded and has possible negative consequences for sleep.  As the authors themselves put it in the abstract of their article

“Room-sharing at ages 4 and 9 months is associated with less nighttime sleep in both the short and long-term, reduced sleep consolidation, and unsafe sleep practices previously associated with sleep-related death.”

Those are some pretty strong suggestions for a study and as the authors call for the AAP to revisit their entire stance on room-sharing, it begs the question of what type of research they have to back this up and whether or not it is warranted.  Furthermore, outside of this one study, it is worth examining the idea of babies sleeping alone and what we know about this practice as it is so biologically and evolutionarily abnormal.  But let’s start with the study at hand.

What is the INSIGHT Study?

The first thing we need to look at is what kind of data collection are we looking at here.  The data comes from the INSIGHT study which is an ongoing, prospective, randomized, controlled trial evaluating an intervention to prevent childhood obesity.  Families in the Pennsylvania area are recruited and randomly assigned to either a control group or intervention group.  As described on the study’s site, “The parenting intervention messages are related to responsive feeding, division of feeding responsibility, and healthy dietary choices designed for the prevention of obesity that extend from infancy through age 3 years. These materials also contain messages relating to sleep, active social play, and child fussiness/soothing. The control group receives messages focused on the safety of the child’s environment and interaction with parents.”

Looking at the study methodology in depth, I want to highlight a few things that cause concern:

  1. One of the researchers in this cohort (not an author in the current article) is known for pushing sleep training and modern sleep techniques. In fact, it is her book that is cited as “expert sleep guidance” when contradicting the AAP message.  This doesn’t in and of itself matter, but it speaks to the idea that there are pre-existing biases that these researchers have when it comes to sleep.
  2. The sleep portion of this intervention is based on sleep training. Specifically, they focused on teaching families to utilize short routines, no feeding to sleep, early bedtimes, and “the importance of self-soothing to sleep and after night wakings”.  Their sleep guidelines also include transitioning babies to their own room by 3 months of age.
  3. Feeding guidelines include avoiding overnight feeds by 4 months, don’t wake a baby to feed them, no feeding to sleep (as mentioned above), and the importance of sharing feeding duties (which of course, implies bottle feeding).

The current examination groups the control and intervention group, but of course there are bound to be differences between them.  The control group may not have weaned a child off feeds or have been conditioned to ignore their child at night.  These are important elements that need to be considered when we look at the data as a whole.  We also need to be aware that this study is really all about moving infants away from what is biologically normal.

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Does Room-Sharing Lead to Worse Sleep?

One of the main findings that is getting lots of traction in the media is the idea that babies who sleep independently early get “better” sleep as measured by more sleep and greater consolidation.  Of note, herein independent sleep is simply sleeping in one’s own room and not room-sharing per the AAP’s guidelines.  According to this study – which included 230 mother-infant dyads – infants who were sleeping independently at 4 months were getting 40 min more sleep (on average) at 9 months and those who were sleeping independently at 9 months were getting 45 min more sleep at 30 months.  At 4 months, independent sleepers had longer stretches of sleep (but not total duration of sleep) and fewer feeds at night (this makes sense given the intervention material stated above).

This may sound all fine and dandy, except these findings actually have two MAJOR errors that basically invalidate their conclusions.

So what are these major problems?

Source: North Country Neurology

Most importantly, infant sleep is parent reported. Although this had been a staple of understanding infant sleep for years, research that has examined parent report relative to actigraphy[2][3][4][5] has found that the two diverge quite readily.  Importantly, infants are waking and up much more than parents believe them to be and this is going to be much more likely to be the case when infants are separated from their parents.  A baby who rouses briefly in their own room is unlikely to get the attention of a parent, but one who does while sleeping next to mom is more likely to be noticed.

To highlight how discrepant this difference can be, we can look at one of the larger studies that included actigraphy to assess infant sleep[2].  In this study, parent diary reports included the number of night wakings they were aware of as well as actigraphy measures of wakings.  At baseline, families reported an average of 3.1 wakings per night; however, actigraphy found that infants were waking up on average over 8 times per night.  This intervention study also found that although parents who were in the intervention group – which was aimed at teaching independent sleep via controlled crying – reported much improvement in their baby’s sleep relative to the control group, actigraphy again found that there was no difference in sleep quality for babies.  They were not sleeping longer or waking less, even though parents reported they were.

Interestingly, the researchers do not completely ignore this, stating that they are aware research has found no differences in sleep depending on where a child sleeps[4][5].  However, they argue that this only reinforces how bad cosleeping can be for mothers.  As they state, “However, this possibility, if true, would only reinforce the concept that room-sharing may result in either unnecessary parental responses to infant night wakings or, alternatively, the infant’s expectation of caretaking behaviors from parents, both of which can be expected to lead to decreased sleep for infant and parent.” (p 7)  Now, as we know, it doesn’t lead to worse sleep for infants and as for mothers, although some would suggest maternal sleep is worse (e.g., [4]), this contradicts research that has found breastfeeding, cosleeping dyads sleep better than their solitary sleeping counterparts[6][7].

The second error is that this study fails to consider the third variable problem. That is, it is entirely likely that there is a child characteristic that has an influence on where they sleep and how well they sleep.  A child with a feeding problem will wake more to feed more and is more likely to be kept close to facilitate these feedings.  Similarly, a child that sleeps through early is more likely to be moved to his or her own room early.

This is important as we look to the 30-month findings that saw lower nighttime sleep in those who were still room-sharing at 9 months versus those who were not.  It seems strange to consider that room-sharing 21 months earlier would have such a profound effect; however, it is not strange to consider that these children could be different in other ways.  For example, more of them may still be room-sharing and thus we simply have more accurate data on sleep duration.  These children may be home during the day and thus napping more (after all, there was no difference in total daily sleep so these children were just napping longer during the day).

Another element that speaks to this problem is breastfeeding rates.  The group that was sleeping alone by 4 months had lower rates of breastfeeding (≥ 80% of the time) than those who were sleeping alone by 9 months; however, the group with the lowest rates of breastfeeding was the group who were still room-sharing at 9 months.  Typically breastfeeding and cosleeping go hand-in-hand and so there is the possibility that there were other issues influencing sleep that simply weren’t assessed and controlled for.  There are many possibilities that don’t speak to solitary sleep as the cause.  Of course, this requires us to accept their sleep data, which we shouldn’t, but provides evidence that even looking at bad data in the best of lights, there is still a major flaw in their conclusions.

To answer the question of whether or not room-sharing leads to worse sleep, the data here does not tell us anything from the perspective of infant sleep.  In fact, arguably the most accurate responses are from those who are room-sharing as these are the families who are most likely to be aware of the movements and wakings of their child.  We certainly don’t have any evidence that there is a causal relationship between solitary sleep and sleep duration.

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Is Room-Sharing Actually Dangerous, as the Researchers Contest?

Photo Credit: NPR

The secondary conclusion reached by these researchers is that room-sharing is actually dangerous because it increases the risk of bedsharing, something the AAP has spoken out against.  The researchers contend that the AAP’s position on room-sharing is not evidence-based as the majority of SIDS deaths occur prior to 6 months and the research the AAP cited does not include cases from 6-12 months.  Furthermore, they suggest that the hypothesized protective mechanism in room-sharing may actually be due to bedsharing:

Although the Task Force’s recent letter cited more frequent arousals among room-sharers as the potential protective mechanism, the 2 studies referenced do not support that conclusion. The first is a case-control study of 18 infants.‍ Among 9 roomsharers, 5 were bed-sharers, making conclusions about arousals among those who are room-sharing but not bed-sharing (versus independent sleepers) problematic. The second study, which also included bedsharers in the room-sharing group, states that parental presence in the room at bedtime (eg, holding, rocking, feeding to sleep) explained much of the variance in night wakings and that night-long roomsharing had a “negligible (<1%) independent contribution to the explained variance.”

These researchers then go on to say that the biggest problem with the room-sharing recommendation is that higher likelihood of bedsharing at 4 and 9 months and therefore a greater risk of SIDS.  Because of this, the AAP should revisit their recommendations to room-share for the first year of life when a transition is harder on babies because of separation anxiety.

While I actually appreciate their thoroughness in this regard, I want to point out some of the flaws in their own reasoning here:

  1. Yes, they really did suggest that the potential protective effect attributed to room-sharing may be due to bedsharing and then turned around to claim bedsharing was inherently dangerous.
  2. Bedsharing is not inherently dangerous, but rather can be done in a dangerous manner. The AAP has acknowledged this in their recent statement on safe sleep in infants greater than 4 months of age[8].  However, even if we accept older views on the issue of safety with bedsharing (which we shouldn’t, but I’ll play along), the consensus is that bedsharing after 3 months of age carries no additional risk for SIDS versus other sleeping arrangements[9].  Given the researchers are concerned about more bedsharing at 4 months and 9 months of age, they really ought not to be.
  3. They seem to agree that room-sharing under 6 months could be protective against SIDS, but are speaking about solitary sleep at 4 months without explaining themselves and their intervention pushes solitary sleep by 3 months of age.
  4. The arousal hypothesis and biological reason for night wakings is one that has been explored in-depth by Dr. James McKenna (e.g., [10][11]), which is wholly ignored here by these researchers. I recommend everyone take a good look at what he has covered.
  5. The researchers seem to not realize that arousals and night wakings are not the same thing. Not the way they are speaking about them.  Babies arouse briefly throughout the night and many of these arousals do not wake or even catch the attention of parents unlike a full waking.  Thus the suggestion that bedtime routines influence night wakings and thus there is no merit to room-sharing belies a real misunderstanding of the arousal hypothesis.  Again, read Dr. McKenna’s work.
  6. Notably, second study referenced above included another publication that looked in-depth at these cross-cultural differences and it’s worth noting that they found much higher rates of bedsharing and room-sharing in predominantly Asian cultures versus predominantly Caucasian cultures (64.65% vs. 11.80% for bedsharing and 86.47 vs. 21.95% for room-sharing)[12]. Why mention this?  Because the predominantly Asian countries have lower rates of SIDS.

So is room-sharing actually dangerous?  Should the AAP revise their stance?  No and perhaps.  No, room-sharing is not dangerous, but the AAP may want to look more into this link with bedsharing and a protective mechanism.  Perhaps we can convince the AAP to suggest safe bedsharing for a spell?

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Is There Cause to Worry About Solitary Sleep for Infants?

Not too surprisingly, the researchers seem to ignore some very important elements in their rush to claim cosleeping can have negative consequences for families and the AAP ought to revisit its recommendation to push early solitary sleep.  Most importantly I want to reiterate that this entire intervention is based on moving families away from what is biologically normal.  It was a pity to see not a single reference to either Dr. McKenna or Dr. Ball, both of whom have looked at the evolution and biology of maternal-infant sleep in depth and whose work should not be ignored here.  I strongly recommend anyone interested look up their work (much of which is cited in my various articles on sleep) and see what we know about mother-infant sleep from a much more complete perspective than we see in this study.

One of the other elements that is conveniently ignored in this piece (and others on the INSIGHT study) is that there may be evidence that solitary sleep increases the risk of insecure attachment[13].  Now, to be fair here, the research on attachment and sleep location is very preliminary and requires more follow-up to be able to make any conclusion.  However, the current study is also quite flawed and any recommendation should not be made on the basis of this study alone.  If one wants to take anything from this, one should also take into consideration other studies that also require far more detail and follow-up or replication before making any conclusions.

The final issue that was ignored entirely by the researchers is breastfeeding.  We can see a bias against breastfeeding when we look at the intervention being promoted.  In no way is it biologically appropriate to cut all night feeds by 4 months of age and expect no effects on supply.  Further, if the feeding of an infant under 6 months is shared, then it is likely that supplementation is being used (though of course expressed breastmilk could be used too).  Clearly the intervention is not geared towards the realities of breastfeeding mothers, but that is simply not part of any discussion herein.  The ignorance of how breastfeeding and cosleeping work together is hugely problematic and I refer you to an excellent summary of these issues here by IBCLC Meg Nagle who has covered the bases on this one.

So is there reason to worry about solitary sleep?  For some families, yes.  And this highlights one of the most frustrating parts of this research: the lack of nuance.  On top of simply ignoring mother-infant biology, the researchers blithely ignore that families have their own considerations that can make any sleeping arrangement problematic.  One of the things the recent AAP guidelines tried to do (though still fell far short, in my opinion) was to create a bit of nuance to allow caregivers to work with people instead of rules.  Frankly we would all be better off if that approach was taken in any discussion of infant sleep.

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[1] Paul IM, Hohman EE, Loken E, Savage JS, Anzman-Frasca S, Carper P, et al. Mother-infant room-sharing and sleep outcomes in the INSIGHT study.  Pediatrics 2017; 140: e20170122.

[2] Hall WA, Hutton E, Brant RF, Collet JP, Gregg K, et al. A randomized controlled trial of an intervention for infants’ behavioral sleep problems.  BMC Pediatrics 2015; 15: 181.

[3] Gradisar M, Jackson K, Spurrier NJ, Gibson J, Whitham J, et al. Behavioral interventions for infant sleep problems: a randomized controlled trial.  Pediatrics 2016; 137: e20151486.

[4] Volkovich E, Ben-Zion H, Karny D, Meiri G, Tikotzky L. Sleep patterns of co-sleeping and solitary sleeping infants and mothers: a longitudinal study. Sleep Med 2015; 16: 1305–12.

[5] Teti DM, Shimizu M, Crosby B, Kim BR. Sleep arrangements, parent-infant sleep during the first year, and family functioning. Developmental Psychology 2016; 52: 1169–81.

[6] Rudzik AEF, Ball HL.  Exploring maternal perceptions of infant sleep and feeding method among mothers in the United Kingdom: a qualitative focus group study.  Matern Child Health J 2015; DOI: 10.1007/s10995-015-1798-7.

[7] Quilin IM, Glenn LL.  Interaction between feeding method and co-sleeping on maternal and newborn sleep. Journal of Obstetric, Gynecologic & Neonatal Nursing 2004; 33: 580-8.

[8] Task Force on Sudden Infant Death Syndrome. SIDS and other sleep related infant deaths: updated 2016 recommendations for a safe infant sleeping environment.  Pediatrics 2016; 138: e20162938.

[9] Carpenter R, McGarvey C, Mitchell EA, Tappin DM, Vennemann MM, et al. (2013). Bedsharing when parents do not smoke: Is there a risk of SIDS? An individual level analysis of five major case-control studies. British Medical Journal Open 2013; 3: e002299.

[10] McKenna JJ, McDade T. Why babies should never sleep alone: A review of the co-sleeping controversy in relation to SIDS, bedsharing and breast feeding. Paediatric Respiratory Reviews 2005; 6: 134-152.

[11] McKenna JJ, Ball HL, Gettler LT. Mother-infant co-sleeping, breastfeeding and sudden infant death syndrome: What biological anthropology has discovered about normal infant sleep and pediatric sleep medicine. Yearbook of Physical Anthropology 2007; 50: 133-161.

[12] Mindell JA, Sadeh A, Wiegand B, How TH, Goh DYT.  Cross-cultural differences in infant and toddler sleep.  Sleep Medicine 2010; 11: 274-80.

[13] Mileva-Seitz VR, Luijk MPCM, van Ijzendoorn MH, Jaddoe VWV, Hofman A, et al. Association between infant nighttime-sleep location and attachment security: no easy verdict.  Infant Mental Health Journal 2016; 37: 1-12.