The Last Word on Sleep Training?

In a study published in the journal Pediatrics this week [1], an Australian research group found no evidence of harm in kids that were sleep-trained, 5 years after the fact. This is the longest follow-up study of sleep training to ever be published, and it’s a randomized controlled trial no less.

Not surprisingly, the media has jumped all over this study with headlines like this one from the Huffington Post: “Baby Sleep Training Methods Safe For Infants.” (The best part about that article is that, below it, there is a link to another HuffPo article from last December entitled, “Cry It Out: The Method That Kills Baby Brain Cells.” That’s a great demonstration of how much the media loves this story and why parents are probably sick of hearing judgment on it either way.)

Parents – particularly those of us who sleep-trained our kids and enjoyed the benefits – are breathing a sigh of relief. I’m happy if the coverage of this study allows parents to shed an unwarranted layer of stress and guilt. If you’ve been following my blog for a while, then you know how I feel about sleep training. After reviewing the literature on this topic, I have concluded that there is no evidence that sleep training harms kids. In contrast, there is a significant body of literature that sleep deprivation poses very real risks to families and that sleep training is often helpful in these situations. It may not work for all babies and parents, but when it does, it can make all the difference.

So where does this new study fit in with the previous research in the field?

I have read several earlier reports from this group – starting with the initial outcomes of sleep training when these kids were infants [2] and following up with them at 2 years of age [3]. By looking at these kids at 6 years of age, this study is addressing a very real concern among parents. However, it had some major limitations, which have barely been mentioned by the mainstream media.

First, let me summarize the nuts and bolts of this study and what it tells us. Bear with me…

The study included 328 families with 7-month-old babies. The mothers of these babies had all answered “yes” to the question, “Over the last 2 weeks, has your baby’s sleep generally been a problem for you?”

The study was randomized by maternal and child health centers, where families in Australia take their babies for well-baby check-ups and support. There were 174 families attending the intervention centers and 154 families attending the control centers. At the intervention centers, nurses were trained to offer counseling and advice on babies’ sleep issues. At the control centers, nurses weren’t given any specific training. During the intervention sleep consultation, “nurses elicited the nature of the sleep problem, identified solutions, and wrote an individualized sleep management plan with the mother” [2]. Some mothers were counseled on sleep training methods, including “controlled comforting” and “camping out.” This is actually the first time I’ve heard the term “controlled comforting.” It is more commonly known as “controlled crying,” graduated extinction, or the Ferber method, and I have to say that this new term is more palatable (and intentionally so, no doubt). All of these names mean the same thing: that baby is asked to fall asleep on her own, with parents coming to offer a little reassurance at increasing intervals until she falls asleep. In the “camping out” method, parents initially stay in the room as baby falls asleep and then gradually withdraw their presence over a period of a few weeks.

Nurses at the intervention centers offered their sleep advice at the 8-month checkup. However, of the 174 families in this group, only 100 actually showed up to receive the intervention. (It isn’t clear if they missed the 8-month checkup entirely or if they specifically avoided the sleep advice.) And among the 100 families that did show, only 56 recalled being given advice about controlled comforting and 21 recalled being given advice about camping out. It sounds like the nurses gave truly personalized advice and must have offered sleep training as an option only when they thought it was a good fit. Most mothers reported being satisfied with the advice they received, but just 56% of them said that they actually used the sleep strategies “most” or “almost all of the time.” (Note that these results aren’t reported in the most recent study – you have to go back to the 2007 study to find them [2].)

Do you see the problem? If I’m reading this right, this means that only about 43 babies were actually sleep trained of the original 174 included in the intervention group. And we have no idea how the control families managed their babies’ sleep problems. Parents turn to many sources of information for advice, and just because these families weren’t offered sleep training advice as part of this study doesn’t mean that they didn’t try sleep training at some point. In fact, an earlier paper from this study noted that the control mothers were significantly more likely than the intervention mothers to seek additional professional help with their baby’s sleep (33% vs. 18%, P=0.02) [2].

Given this, it is kind of incredible that there were significant improvements, albeit small, in infants’ sleep and maternal mental health at 10 and 12 months [2]. By two years, there was no difference between the two groups in the percentage of kids with sleep problems, but the intervention moms were still better off when it came to mental health [3].

In the current study [1], the researchers contacted the original families to see if they would be willing to complete some follow-up assessments now that their kids were 6 years old, including a mailed questionnaire, a home-based assessment, and two salivary cortisol samples. Only 69% of families agreed to the follow-up, 59% participated in the home visits, and 46% gave cortisol samples. That’s not exactly a great turnout.

The assessments covered a slew of measures of child sleep issues, stress, and behavior problems, as well as of the child-parent relationship and maternal depression. The cortisol sample was a measure of chronic stress. Among all of these measures, there were no significant differences between the intervention and the control group. This is the result that all of the news stories are reporting: sleep training causes no long-term harm. It also doesn’t provide a long-term benefit to kids, because in none of these measures were the intervention kids better off. As I already mentioned, earlier studies did show a significant benefit at 1 and 2 years of age [2,3].

I see a couple of major problems with this latest round of data. First, a lot of families were lost to follow-up. This is understandable – it’s real life for you. Families move, and the researchers were unable to contact many of them. Others said they were just too busy, and we can all understand that. However, the study doesn’t report how many of the returning intervention kids actually had some documented sleep training. That would be useful information to know, and the authors have it because they reported it in a previous paper. In their data analysis, the authors included all of the families originally assigned to the intervention group, even those that didn’t actually show up to get sleep advice. This type of analysis makes sense if they are trying to determine the overall effects of offering a parenting advice intervention, but it might miss some effects in the subset of kids whose parents actually followed the advice. Given that this study set out to determine if sleep training caused lasting harm, and only a small percentage of the intervention kids were actually sleep-trained, running some specific analyses on just these children would have helped to convince me that sleep training indeed didn’t have any lasting effects.

One final bone to pick: measures of child and maternal well-being were all based on the mothers’ own reports. Mothers certainly know their kids, but they aren’t always the most objective, particularly when asked to judge the quality of their relationships with their own kids.

Even with its limitations, I appreciate that this study was a randomized controlled trial. This is the gold standard for showing causality – rather than just correlation – of an intervention and outcomes. That adds a lot of strength to the findings of benefits in the earlier papers from this study. Contrast this to a study of cortisol concentrations in sleep-trained babies that came out a few months ago [4]. Although this study was interpreted in the media as showing that sleep training was stressful to babies, no such conclusion could actually be drawn, because there was no control group.

The limitations to this study – that many intervention families didn’t show up for their appointments, many didn’t actually need or want sleep training, many weren’t consistent in their approach to their babies’ sleep, and many didn’t participate in the follow-up study – illustrate just how difficult it is to study parenting behaviors, even with the best study design. Ethically, we can’t force any parent to change their behavior in a particular way based on randomized group assignment. The same difficulty arises when we try to tease out the effects of breastfeeding vs. formula-feeding and cosleeping vs. solitary sleep. For these types of parenting behaviors, all we can really do is what this study did: offer advice to one group of parents and not the other and track outcomes over time. Add to this that there are millions of parenting interactions that happen between the time that these parents struggled with their babies’ sleep and the time they were 6 years old. From a researcher’s standpoint, this makes it awfully difficult to tease out the effects of a couple days or weeks of sleep training at 8 months.

So despite the headlines you’ve been seeing, I don’t think this is the last word on sleep training. I wish it were, because I’m tired of all the guilt tripping I see in parenting conversations about this topic. But no, that’s really not the way science works. No study is perfect in design, execution, and interpretation. This is why it takes a body of evidence, built over time, for us to understand anything. So far, the body of evidence on this topic says that sleep training is an effective way to help most kids get a better night’s sleep, and there is no evidence that it is harmful.

I was trained in science, and I value it immensely. However, I have learned a few humble lessons as a parent. For one, parenting is complex. Science can provide some guidance, but no study can account for all of the ways in which we impact our kids. At the end of the day (literally), we parents are left to try to help our babies find their ways to restful sleep. Science can help. Experienced parents and professionals can help. None of them can provide a roadmap for you and your baby. We have to trust ourselves, follow our instincts, and find what works for us. Maybe it’s sleep training; maybe it’s cosleeping; or maybe we just muddle through. Parent with love and respect, and for goodness sake, don’t worry about what HuffPo has to say about it!.

References:

[1] Price, A. M., M. Wake, et al. (2012). “Five-Year Follow-up of Harms and Benefits of Behavioral Infant Sleep Intervention: Randomized Trial.” Pediatrics. Published online September 10, 2012.

[2] Hiscock, H., J. Bayer, et al. (2007). “Improving infant sleep and maternal mental health: a cluster randomised trial.” Arch Dis Child 92(11): 952-958.

[3] Hiscock, H., J. K. Bayer, et al. (2008). “Long-term mother and child mental health effects of a population-based infant sleep intervention: cluster-randomized, controlled trial.” Pediatrics 122(3): e621-627.

[4] Middlemiss, W., D. A. Granger, et al. (2012). “Asynchrony of mother-infant hypothalamic-pituitary-adrenal axis activity following extinction of infant crying responses induced during the transition to sleep.” Early Hum Dev 88(4): 227-232.

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23 thoughts on “The Last Word on Sleep Training?

  1. Thanks for this write-up! You may have seen mine in Red Wine & Apple Sauce, and I seized on the same limitations that you did. It is driving me crazy that all the mainstream media reporters covering this don’t appear to have even read the study. That 100 out of 174 jumped out at me when I wrote it up for my job (my non-blogging day job is health reporter :) While I looked at the two previous studies’ abstracts, I didn’t pull them up to read fully, so thanks for the info on the recall from the parents. The beef I mentioned in my post was that we have no idea if the parents used one, both or neither option – in either group. I’ll have to go back and check out the first follow-up study. (How annoying that they didn’t include that in the methods for this second follow-up.)

    My reaction, however, was also similar: the good news – whatever choices you make for your child with sleep/sleep-training, chances are they’re going to turn out okay.

    • Thanks for the comment, Tara. I read your post, too, and I appreciated your analysis. I actually think that the initial study (outcomes in infants and 2-year-olds reported in 2007 and 2008) was well-designed and that the statistical analyses were appropriate. It was designed as a community intervention to determine the effects of providing some sleep-specific counseling (which sometimes included sleep training advice) to families that were struggling with their babies’ sleep. This was a real-world intervention with all the limitations that brings, but in that sense it showed that this type of intervention *did* help families in the short- and medium-term. However, this study wasn’t really designed or the data appropriately analyzed to answer the question they posed in this latest study. My guess is that the 5-year follow-up was an afterthought in response to concerns of parents. It’s nice to see, but it isn’t as conclusive as the authors and the media have made it out to be.

      And I agree that it is good news that most kids learn to sleep eventually, whether that process is more child- or parent-led! The same group published another paper a few months ago looking more closely at sleep issues in these kids. If I remember correctly, they basically found that a small percentage of kids seem to have persistent sleep problems through early childhood, and that was the same in both the control and intervention groups. The rest all slept well, eventually. In contrast, sleep training advocates often imply that a baby that struggles with sleep will become a child that struggles with sleep, and that sleep training will change that. I’ve never actually seen good evidence that that is true.

  2. Knowing that you used and defend sleep training and found it very helpful, I wasn’t sure what to expect from your article. Thank you for writing such an unbiased article about this study.

    I think the fact that we don’t actually know what the control group did makes the whole study meaningless. Sleep training advice is around everywhere it is in fact the most common advice when looking for help with a baby’s sleep, whether that is by asking friends and family, on the internet, parenting books etc. I would expect the percentage of babies that were sleeptrained in the control group to be very high. In fact, it could even be that the control group babies were subjected to harsher methods like Cry-it-Out, which was not advised to the people in the sleep-training group.

    • As I said in my comment above, I thought that the original study design was appropriate for determining outcomes of a sleep advice intervention. You’re right that it didn’t specifically test sleep training, since only a portion of the intervention families actually tried these methods and as you say, we don’t know what the control families did. It sure would have been nice for the researchers to poll both the intervention and control families on what strategies they used to try to improve their babies’ sleep so that we had that data to compare. Whatever they did, the intervention families had better outcomes. But yeah, this is my long way of saying that I agree with you:)

    • Thanks for this discussion. I just wanted offer my opinion that controlled crying can actually be harsher than CIO. My first child did not respond to it at all and it made her more and more distressed. We eventually used Save Our Sleep methods, which use a more straightforward CIO and my baby responded much better and quickly learned to fall asleep.

      Diane Levy, a family psychologist notes that in her experience controlled crying only works for about 2/3 of families who try it.

  3. Great summary. I didn’t get to read the paper- I wasn’t going to pay for it, so I appreciate the ‘nuts and bolts’ that weren’t in the abstract. It’s kind of annoying the way the media hype this.

    I posted about it as well- it was good timing for me as the night before I had let my youngest cry himself to sleep.

    However, I cracked up when I saw a post on The Stir (Cafe Mom) that was entitled, “It’s Okay to Let Babies Cry It Out if You’re a Cold-Hearted Scientist“. The poster references that ridiculous blog post from several months ago that I think you addressed on your blog- it was on Psychology Today’s website, had no data, and the media kept calling it an article.

    • Oh wow, I love – and hate – that headline! This debate used to bother me a lot more, but I guess I’ve grown to have enough confidence in my own parenting that I can laugh about it a little. I just hate to see the guilt laid on to struggling parents, and I hate to see parents and babies suffer through horrible sleep because of a PT blog post. Anyway, I hope sleep training your little one is going OK. It’s never easy but can be sooo helpful. Best of luck:)

    • Have you done any sleep studies with him? I know adults who sleep badly who said that was what helped them finally figure out what they needed – often it was a CPAP machine. I’ve yet to hear of a parent doing a sleep study with their child, so it’s something I’ve wondered about.

  4. Terrific summary. I think that this study confirms what those of thus in the pediatric sleep field have believed to be true. (On the other hand, perhaps this is why I am being less critical). think that your criticisms of the study are fairly valid, but I would be surprised if there were to be more research in this vein. Essentially no significant studies have shown significant detriments to sleep training that I am aware, and the benefits are well documented.

    • Hi Craig – I really value your insight into this issue, since I know you are someone on-the-ground working with families struggling with sleep issues. As a clinician, you see these strategies in action and see the effects, and I’m guessing that your level of comfort in recommending sleep training to families where appropriate comes from that experience. That’s doesn’t make an RCT, but it is still meaningful.

      I meant to mention in my post that the authors stated virtually the same thing in their paper: “This 5-year follow-up of a rigorously conducted randomized trial (the gold standard for assessing causality) may represent the only opportunity to provide objective evidence investigating any lasting harms or benefits of behavioral infant sleep interventions. This is because, with their known short- and
      medium-term effectiveness, it is unlikely that new trials with true nonintervention
      controls and 5-year follow-up could now be ethically conducted.” It will be interesting to see if this is true. Would an IRB not approve a future study of long-term effects of sleep training based on this one paper? I’m not sure, because I think it could be argued that this study didn’t fully address the concern.

  5. I’m curious that they mentionned maternal mental health. The link between sleep deprivation and postpartum mood disorders is so obviously huge…but I look forward to seeing more research (and understanding!) on it. Wait until you have a second child (if you are planning on it). It really shows you how each child is so different and what works for one won’t work for the other when it comes to sleep. Plus they constantly wake each other up, which clouds the whole picture considerably, but that’s another story. :)

  6. Thank you so much for your analysis of this study. I was just writing about the topic of sleep and CIO myself from a psychological perspective (and actually mentioned your blog), when I read the Wall Street article that summarized the study’s findings. It’s amazing how little information you get from a summary article like that one, and so I truly appreciate your critical thinking on the matter. I hate to confess that I’ve not done the hard work of looking closely at some studies as you have, and am grateful for your input. I am personally interested in some of the psychological theory behind some of the issues that we struggle with as mothers, but the science and theory go hand in hand. Beyond that, I am in total agreement with your conclusion to this post, and would argue that even more important than both the psychological theory and the science is each person’s gut/instinct/intuition on how to parent.

  7. I really enjoyed reading your experience and research on the science of infant sleep. Thank you for providing a safe and encouraging space for parents/readers to have conversations about a topic that is so personal and emotional to all of us. As parents (especially mothers), we should be supportive of each other journeys to be the best parents possible.

    I am a first-time mum to a 9 week old beautiful baby girl. When I read your description of BabyC’s sleep patterns, I felt like you were talking about my daughter! It was such a relief to learn that we are not the only parents who use the swaddle+baby carrier+exercise ball method (yes, damn that ball!). We still use this method to soothe our baby to sleep but we really want to start helping our baby to learn self-soothing skills and develop healthy sleeping habits. Based on your experience and research, I hope that you would be able to answer some of my questions:
    1) What are your recommendations for helping my baby to self-soothe at her age? Would you have done a milder version of letting her cry a bit at every bedtime and nap?
    2) Did you have to use the Ferber method again after a nursing session or night wakings?
    3) Do you have any suggestions for establishing a healthy nap routine?

    I look forward to reading your responses. Thanks again for sharing your experiences with us!

    • Hi! Congrats on your baby girl! And welcome to the club of ball bouncers:) It’s funny, I’ve cursed that ball, but I also just recommended it to a friend with a new baby a few weeks ago. Next time around, I think I might use it occasionally to help soothe baby, but I’ll be sure that it isn’t the ONLY way my baby knows how to sleep.

      1) In your position, I would just recommend starting to give your baby opportunities to self-soothe. You might bounce for a while to help her wind down, then hold her for a while, then put her down awake. Stay close to her and maybe stroke her tummy and talk quietly to her – or not – whatever you think might help her to wind down. Now, I remember trying this with BabyC, and she would just cry, and I would pick her up pretty quickly. It may work with some babies but not with others. In hindsight, I wish that I’d tried this more and given her a little more time to fuss with me there. But I know it is hard – you just want your tired baby to sleep! If you want her to start learning to self-soothe though, you have to give her opportunities to try it – not every time, but maybe once per day or something. She might surprise you.

      2) We didn’t. Once BabyC was falling asleep on her own at the beginning of the night, she fell asleep after night feedings with no problem.

      3) Naps are hard, and they take longer to get into a good routine than nighttime. At least, that was our experience. BabyC starting having a predictable nap routine around 5 months. We let her cry before naps some, but we also did lots of walking naps and some nursing/holding naps. It was just hard for her to wind down in the middle of the day (but so important!).

      If you haven’t read this post of mine, it has more tips in it. good luck!
      http://scienceofmom.com/2012/04/03/6-little-secrets-of-a-sleeping-baby/

  8. I’m very happy to read this. This is the type of manual that needs to be given and not the accidental misinformation that is at the other blogs.

  9. Very interesting! With my second we are trying not to making the same mistakes as with our first. At what age would you recommend starting? My DD is 4 weeks old. She cries when we put her down awake, is it too young to leave her for 5 minutes before soothing her again? Thanks!

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