How Your SNOO Is Keeping Your Baby From Rolling
The Snoo is marketed as the ultimate smart bassinet, offering sleep-deprived parents the promise of longer, more restful nights. One of its key features is that it keeps babies safely on their backs, reducing the risk of SIDS. But from a physical therapy and developmental perspective, a machine responding to your baby’s needs and preventing your baby from rolling can have unintended consequences.
Let’s talk about this because I know it’s not a comfy conversation.
How the Snoo Prevents Rolling
The Snoo uses a built-in swaddle system that secures babies in place, keeping them on their backs at all times. This means that, unlike traditional bassinets, where babies can naturally start to explore movement, Snoo babies stay in a fixed position until they transition out of the bassinet.
While this might sound like a great safety feature, it also means that babies don’t get the opportunity to practice rolling—their first major gross motor milestone—as much as babies who are in a sleep sack starting at 8 weeks.
Why Rolling Matters
Rolling isn’t just a cute milestone—it’s a crucial part of motor development. When babies learn to roll, they’re:
Developing appropriate range of motion in their arms
Developing coordination between their upper and lower body
Strengthening their core, back, and neck muscles
Improving balance and spatial awareness
Building the foundation for crawling, sitting, and walking
By keeping babies in a position where they can’t roll, the Snoo may inadvertently delay these important skills.
The PT Perspective: The Downsides of Restricted Movement
As a physical therapist, I see many babies who have difficulty with movement patterns after prolonged time in restrictive devices. When a baby spends months in a Snoo, they may miss out on:
The natural process of shifting weight and using their muscles to adjust position
Early opportunities to push through their hands and build strength in their shoulders
The ability to practice head control in different positions, which is crucial for preventing head flattening (plagiocephaly) and torticollis (yes- unfortunately many of the babies I see in Snoos are the ones who get the helmets)
If babies come out of the Snoo at four months, they suddenly find themselves in a crib without the ability to move, feeling very unhappy because they haven’t been given the chance to practice.
The Responsiveness Factor: Babies Need Human Soothing
One of the selling points of the Snoo is that it responds to a baby’s fussing with increased motion and white noise. While this might help babies fall back asleep, it replaces human responsiveness with a machine.
Babies cry to communicate, not just to get back to sleep—they may be hungry, uncomfortable, or in need of connection. If a device is soothing them before a caregiver even gets the chance to respond, it can interfere with the natural attachment process, and even sometimes lead to poor weight gain in babies who really do need to eat every few hours at night.
(Yes… babies DO need to eat every few hours at night… this is normal and expected.)
So What’s the Alternative?
If you’re concerned about safe sleep and YOUR sleep but don’t want to restrict your baby’s movement, here are some options:
Use a traditional bassinet with a swaddle that allows for natural movement of the arms and legs.
Encourage supervised tummy time ALL THE TIME during the day to build strength and motor skills. Always remember to be respectful of your baby’s tummy time experience.
If using the Snoo, transition out of the swaddle as early as possible to allow for more natural movement… just use it like a bassinet.
Final Thoughts
It’s important to weigh the pros and cons of any baby container you purchase. While it keeps babies safely on their backs, it also prevents natural movement, which is key for healthy development. If you choose to use one, be mindful of ways to encourage movement and responsiveness in other areas of your baby’s routine.
Babies are meant to move. Giving them the opportunity to do so on a firm surface—day and night—helps them build strength, coordination, and confidence in their bodies. It also might mean they will roll exactly when they are meant to roll. Finally, they will learn that when they cry, you respond.
And that’s something no smart bassinet can replace.
I want there to be evidence on this- but it is incredibly difficult to study, as parents have such strong opinions about infant sleep.
Overall, the quality of the evidence out there is poor. There are systematic reviews out there- but the conclusions are… well… inconclusive. Here is what the evidence says.
The SNOO website will point you to studies on NICU babies who have had wonderful outcomes using the SNOO (attached to monitors, predisposed to developmental delay anyway, and likely not yet 3 months old adjusted, trying to work on rolling)
Consumer Reports does discuss concerns for infant motor development and head shape concerns… but as reserach is always emerging, I encourage you to remember that evidence based care includes 3 aspects of evidence (I teach this when I teach my DPT first years at Pacific Univerisity. Yes, the research, but very importantly your clinical experience, and finally, the family’s experience, thoughts, and needs.
It all matters here.
And what matters more than if you use a SNOO or not?
What you do when baby is awake!
Final, final thought here. If your baby is predisposed for some reason for developmental delay, the SNOO will make that worse. If they are going to develop along a typical trajectory, the SNOO will likely not get in the way of that too much (unless it impacts their head shape!)
Okay, I’m now done.
References
Dixley A, Ball HL. The effect of swaddling on infant sleep and arousal: A systematic review and narrative synthesis. Front Pediatr. 2022 Nov 30;10:1000180. doi: 10.3389/fped.2022.1000180. PMID: 36533224; PMCID: PMC9748185.
Gellasch P, Johnson S, Walsh TA. The Experiences and Perceptions of Neonatal Clinicians When Using a Responsive Bassinet. Adv Neonatal Care. 2023 Aug 1;23(4):E88-E95. doi: 10.1097/ANC.0000000000001086. Epub 2023 Jul 6. PMID: 37433179; PMCID: PMC10371059.
Nelson A. M. (2017). Risks and Benefits of Swaddling Healthy Infants: An Integrative Review. MCN. The American journal of maternal child nursing, 42(4), 216–225. https://doi.org/10.1097/NMC.0000000000000344
Singh JK, Menahem S. The five "S's" and the "SNOO" Smart Sleeper-non-pharmacological interventions (NPI) to promote sleep and reduce crying of infants: a scoping review. Transl Pediatr. 2023 Aug 30;12(8):1527-1539. doi: 10.21037/tp-23-42. Epub 2023 Aug 14. PMID: 37692540; PMCID: PMC10485641.
