A quick note: there was a lot of internet discussion last week of the impacts of child care on kids, touched off by a JD Vance tweet and editorial in the WSJ. (No, I’m not going to link to it, since it’s mean to me and I’m petty and this is my newsletter.) I thought about addressing that at length here, but the truth is that I think I cannot do it justice even in the lengthy newsletters I write. I talk a lot about this in Cribsheet. So if you’re dying to see why I disagree with JD, please check it out there.
Today, however, we are going to tackle a different question. Specifically: do you need a SNOO?
“What is a SNOO?”, some of you are asking. Fair enough. Here’s the link. The SNOO is, basically, a robot bassinet. It’s intended to be used from birth to six months, with the goal of improving infant sleep. To greatly simplify, you swaddle your baby (using their swaddle) and strap them into the bassinet. And then the SNOO kind of auto-soothes them (that’s the idea, anyway) with white noise and rocking which is responsive to their movement. If it doesn’t work, then the bassinet messages you to tell you your kid is really grumpy and you need to come deal with it yourself.
The SNOO is the brainchild of Harvey Karp, the creator of Happiest Baby on the Block, which was originally a book and videos, which many of us swear by. (Full disclosure: in addition to being a devotee of Karp’s 5-Ss, he blurb-ed my first book. However, we have never met and I did not speak to him about this post). The 5-Ss are a method for improving infant sleep, involving swaddling, holding the baby in a side-stomach position, shushing, swinging and sucking (a pacifier). The idea with the SNOO is that the robot does a lot of this for you, and keeps the baby asleep longer.
But, does it work?
First: we should ask a question of what do we mean by “works”? Generally, I’m going to talk below about the evidence on improving sleep. But it’s worth mentioning first that the SNOO is also pitched as a way to reduce the risk of SIDS. In fact, the company has submitted for FDA approval as a SIDS prevention device, I think largely based on the fact that infants are strapped onto their back and back-sleeping is known to be the safest position. FDA approval for this claim is pending, but it seems important to mention here.
But I’m going to focus on the question of whether the SNOO works in terms of sleep quality. I will ask the question in three parts: (1) Does it seem like it would work based on other things we know? (2) Do people say it works? (3) Is there any actual data?
Does it seem like it would work?
The main reason is we have good data that the individual parts of the 5-Ss can work. For example, there is a lot of excellent evidence showing that swaddling improves infant sleep. I review a lot of this in Cribsheet; some of it is really in the weeds and involves bringing babies into sleep labs and attaching monitors to them and so on. The bottom line result is that swaddling infants increases the length of sleep spells, likely by reducing the risk that small sleep disruptions ultimately cause the baby to wake up.
White noise also seems like it helps, as you can see in this small randomized trial from several decades ago or this one, which compares white noise to swinging and favors white noise. (I know a lot of you will ask: I thought white noise was bad for hearing? I will try to cover this in a later letter.)
All of these together (actually, not the pacifier) have also been tested in at least one randomized trial, here, and shown to be effective.
So there is good reason to think the S-s work and, by extension, you would kind of expect the SNOO to work, at least relative to doing nothing. I think a reasonable question to ask — not answered by this baseline evidence — is how much better this is than just a white noise machine and a miracle blanket. The responsive aspect of the SNOO, including both the noise adjustment and the swinging, is kind of the key features, but that’s not something we can evaluate based on this data.
Do People Say It Works?
Many of them, yes.
Example blog post. On Amazon, 78% of the ratings are 5 stars.
Not everyone is converted. I did a (totally unscientific) poll on Instagram. After about 6000 votes, 60% of people said it worked for them, versus 40% no. This was somewhat lower than I expected, and the comments were illustrative. I got everything from “This changed my life. AMAZE!” to “The swinging gave my baby motion sickness and they threw up every time.” Many comments were nuanced: basically, my baby slept well, but I don’t know if there was a causal relationship with the SNOO. My readers are nothing if not of a type.
If I had to summarize the comments, I would say that there is clearly a sizable share of people who found it not just useful but life-changing. Some of this group told me that anyone who says otherwise obviously didn’t read the directions. However: it doesn’t work for everyone, or every baby. And for many people they thought it helped, but it wasn’t magic.
(This is an argument for experimenting; see below on the “rental” option).
Does the DATA say it works?
Basically, there isn’t much data. The one thing I could find was this abstract (abstract = a very very short research report) in the journal Sleep in April 2020. The paper, written by Harvey Karp and two coauthors, reports on about 7100 parents who used the SNOO and compares the sleep experienced by their babies over the first six months to that of a reference population from other studies. (Thanks to one of the authors, Dr. Okun, for details about the study not in the abstract).
The abstract suggests that the parents using the SNOO had babies who slept for longer periods and had longer total duration, as well as fewer night wakings (on average 1 per night in the 0 to 6 month period versus 2 in a reference population).
The data for the study comes from the app associated with the SNOO, which is a nice way to collect a lot of data passively, but does mean that the sample is going to be selected in particular ways (both in terms of demographics and perhaps in terms of their attitudes towards sleep.) The reference population they are compared to is based on some other studies (which are unspecified) making it difficult to subject to any scrutiny. I cannot tell whether the populations or data collection approaches are at all similar. This is the nature of an abstract like this; the authors tell me they are preparing a longer paper, which will presumably answer more of these questions. As it is, I do not take very much from this.
The ideal study would randomize access to the SNOO, perhaps comparing with advice to use the 5-Ss without SNOO provision. I hope we will see this! Until then, I think what we might say is there is a lot of reason to think this would work, but relatively little hard data to know exactly how large the effects are.
Are There Risks?
We covered the SIDS risk which, in fact, isn’t a risk at all but possibly a benefit.
The one risk I have seen discussed (largely on social media) is the idea that the SNOO might contribute to “Container Baby Syndrome” which is a constellation of developmental problems that are thought to arise from a baby spending too much time containers (car seats, bouncy seats, jumpers) and not developing appropriate motor skills.
The thing is, that outside of a few social media mentions, I have seen nothing that would suggest the SNOO has anything to do with this. Yes, the infant is swaddled, but that’s likely to be true even without the SNOO. Your infant will be on their back in a crib of some type, hopefully asleep, in any case. The SNOO is no more container than a non-robot bassinet.
What’s the Downside?
The SNOO is expensive. That’s the issue. In some ways, I was reluctant to even write about this because even acknowledging the idea of getting a $1500 robot crib seems a little excessive. Especially for something you will at most use for 6 months, perhaps less. This cost is part of the reason why I hope we might sometime learn something about effect sizes.
However: I will say that there are ways to make this cost less. Happiest Baby offers a rental program; this is especially good if you aren’t sure. Or you can buy a used one. Or you can chip in with your friends and pass it around if you time your babies right. If the FDA does approve it as a SIDS prevention device, insurance may cover some of the cost.
Economics is all about tradeoffs, and this is one. It’s an expensive item, which seems like it might deliver some benefits of uncertain size. It’s worth giving some careful thought to what else you might do with those funds, as part of your decision. Plus, how much do you like sleep?
Keep the thoughts coming. I don’t always write back, but I read everything.
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