Should You Buy a Snoo Smart Bassinet for Your Newborn?
Parents love the popular baby bed. Here’s what experts want you to know.
The Snoo is a smart baby bassinet that gently rocks and plays white noise to calm fussy newborns—and, theoretically, gives parents some of their nighttime sleep back.
By Angela Lashbrook
“You have to write about the Snoo,” my friend said. We were at dinner, and she had recently told me she was pregnant with her first baby.
“The what?” I said.
“The Snoo. It’s a ‘smart’ bassinet. The parents I’ve talked to literally will not shut up about this thing. As soon as I tell anyone I’m pregnant, it’s one of the first things they ask me: ‘Are you getting a Snoo?’”
I became fascinated with the device. How much could a smart “bassinet” help a baby sleep? Is it worth the cost? And are there any risks involved in having a baby in an internet-connected bed that plays noise and moves back and forth? While my friend was preparing for and having her little one, I spent the past several months researching the Snoo, talking to pediatricians, digital privacy experts, infant sleep consultants, pediatric physical therapists, and parents about the Snoo. (Like other sleep-related products for infants we’ve written about in the past few years that would require human-testing, Consumer Reports cannot test this product in our labs, but we rely extensively on research and interviews with experts.)
Many parents love the Snoo. Several of those I spoke with said that the product seemed to help fussy babies sleep—allowing their exhausted caregivers much-needed rest, as well. But despite its cult status among parents, parenting magazines, and design enthusiasts, medical experts who work with babies expressed concerns about the bassinet when I reached out to them with questions about the Snoo.
Here are key points for new parents to consider about the Snoo based on my reporting.
What Is the Snoo?
Does the Snoo Help Baby Sleep?
How the Snoo Works
White Noise and the Snoo
Questions With the Swaddle
Digital Privacy and the Snoo
Weaning Your Baby Off the Snoo
What Is the Snoo?
The Snoo is a popular, $1,595 smart baby bassinet that gently rocks and plays white noise to calm fussy newborns—and, theoretically, gives parents some of their nighttime sleep back. It was created by pediatrician Harvey Karp, MD, alongside Deb Roy, professor of Media Arts and Sciences at MIT, and Swiss designer Yves Béhar. Karp launched it as the hallmark product of his company, Happiest Baby, in 2016. It can be rented for $159 a month plus fees, return shipping, and deposit.
Since its introduction, the Snoo has catapulted to baby hall of fame. It’s won multiple awards, including the 2018 Industrial Designers Society of America “Curator’s Choice,” the 2018 “Best Bassinet” award from The Bump, and the National Sleep Foundation Inaugural SleepTech award. It’s beloved by legions of parents, who claim it helps their baby sleep better, longer—and, in so doing, helps parents sleep better.
In 2020, it was accepted for inclusion in the Food and Drug Administration’s Breakthrough Device Program, which allows manufacturers access to faster FDA review of new health products that have the potential to better treat medical conditions than other products currently on the market. Happiest Baby and the FDA are currently in an “active dialogue,” says Karp, as the Snoo continues to undergo review as a product that, Happiest Baby claims, has the potential to prevent sudden infant death (SIDS) and sudden unexpected infant death (SUID). “At the end of this process, the FDA could decide to authorize the product for reducing the risk of SIDS,” says an FDA spokesperson.
Karp says the Snoo is more of a 24-hour “robotic caregiver” than a mere baby bed. Its internal microphones pick up when the baby inside it begins to cry, and it responds with vibration and white noise. If the baby continues to cry, the Snoo increases the intensity of its movement and white noise.
The Snoo has five movement levels. At its lowest setting, the bassinet shifts slowly back and forth, while at its highest, its jostling is similar to driving on a road in need of the infrastructure bill. The white noise has a similar trajectory: Its all-night level is between 65-70 decibels (about the level of a typical adult conversation), says Karp, while its highest level—which kicks in when the baby is really wailing—is 86 decibels (approximately as loud as city traffic).
The product incorporates elements from Karp’s 2002 bestselling book, "The Happiest Baby on the Block." In the book, Karp details his “5 S’s” (often known as the Happiest Baby Method), which he says are the secret to calming a fussy baby. These “s’s” are swaddle; side or stomach position; shush; swing; and suck. (Babies should only be calmed in side and stomach position; it isn’t for sleeping.) The Snoo uses swaddle, swing (though it is not an actual baby swing; really, it rotates back and forth in a rocking motion more than it swings); and shush to help the baby chill out and sleep through the night (as much as possible, anyway).
Does the Snoo Help Baby Sleep?
Alisa Richter, a New York-based parent of two young children, rented the Snoo out of concerns about her baby’s sleep. She says the first couple of days home from the hospital were “hellish,” as her baby had a lot of trouble sleeping, so she ordered a rental on a whim. “I loved it. It soothed him to sleep and alleviated a lot of my own postpartum anxiety,” she says. “It’s not essential, but I like the extra comfort it provides.” She had first heard about the Snoo when she attended a presentation about the product at a restaurant and event space called A/D/O in Brooklyn. Her second child, a newborn, also sleeps well in the Snoo, she says.
Product reviews, online blogs, and countless other online testimonials attest to how many parents report success with the Snoo’s ability to calm their baby. To date, there has been only one independently published, peer-reviewed full study using the Snoo that Consumer Reports was able to find. The small 2019 study, published in the scientific journal PLOS One, looked at how the Snoo calmed 69 infants, compared with how well babies were calmed when they were swaddled in their parents’ arms, rocked, and shushed by their parent. “We found that babies responded with a calming response to swaddling, movement, and sound when soothed with the Happiest Baby method and with the Snoo—less observed fussiness and lower heart rate” when compared to sitting with the baby, or laying the baby on their back, says Eline Möller, now a senior researcher at Amsterdam University Medical Center (she conducted the 2019 study through the University of Amsterdam). She’s in the middle of a new, small-scale study featuring the Snoo.
John Belanger of California and his wife loved the Snoo for their infant. “Our baby slept well in the Snoo, which helped us—mom and dad—sleep, too, because it did such a great job. It gave us peace of mind knowing that our baby was safely and comfortably swaddled,” he says. He says he has friends who also considered, but passed on, the Snoo, as they weren’t convinced it would make “a meaningful difference in keeping their baby asleep for longer throughout the night.” He notes, however, that he can’t be 100 percent sure his baby’s thorough nighttime sleep was because of the Snoo. “Perhaps our baby is just a good sleeper; can’t say for sure. Whether it was our baby or the Snoo, all of us (baby and parents) got good sleep.”
How the Snoo Works
Babies wake up in the middle of the night for a wide variety of reasons. Oftentimes, the baby needs attention, such as if they’re hungry or need a diaper change. But sometimes babies awaken because they feel or hear something—a draft from an open door, a dog barking, a phone ringing—and, like any person, wake up and can’t fall back to sleep. Typically, if a baby starts crying in these situations, a parent will pick them up, take care of whatever need the baby has (such as eating), and then sing and rock them to sleep.
The Snoo is designed to step in with the shushing, rocking, and swaddling that would otherwise keep the parent awake as they try to coax their baby back to sleep. When the baby begins to wiggle and cry, the bed responds by rocking back and forth, escalating the rocking and white noise if the baby’s fussing doesn’t ease. The bed has five rocking levels, ranging from the level of movement a baby feels in a caregiver’s arms to the jostling one feels in a car on a bumpy road. The bottom, “blue” setting is designed to be left on all night, gently shushing and rocking the baby in an attempt to keep them asleep as long as possible. And if the baby doesn’t stop crying after a couple of minutes and the bed’s increasing rocking and white noise, it turns off. Snoo’s user guide says that if the Snoo has “time out,” parents should attend to their baby.
Parents can elect to use an app to track the baby’s sleep habits, including the baby’s wake-ups, and sleep duration. Parents can also use the app to get alerts about the baby’s movement and remotely control the bassinet, but the app isn’t required to use the Snoo, and more privacy-oriented parents can choose to control the bed using the button on its front rather than relying on a WiFi-controlled phone app.
To keep the baby securely in place during the bed’s rocking motions, the Snoo comes with a proprietary swaddle called the Snoo Sleep Sack that clips into the sides of the bed.
Despite its cult status among parents and design enthusiasts, medical experts who work with babies expressed concern about the product when I reached out to them with questions about the Snoo.
White Noise and the Snoo
One of the hallmark features of the Snoo is its built-in white noise machine. It can’t be turned off when the Snoo is on, meaning that unless parents want to use the Snoo completely off (as if it were a regular bassinet), they and their baby are locked into some level of white noise. According to Karp, the Snoo’s baseline white noise level is between 65 and 70 decibels at the baby’s ear—about the sound of a normal conversation or an office space (the Happiest Baby website lists the sound level between 68 and 70 decibels). Its orange level, which plays when the baby is very upset and crying loudly, is 86 decibels, which is as loud as city traffic.
Not only does the Snoo require the use of white noise, Karp also recommends continued use of white noise for up to two years after the baby has outgrown the bassinet. Happiest Baby sells the SNOObear, a responsive plush “lovey” that plays white noise for babies and toddlers for 30 minutes to an hour at a time.
Limited research has found that white noise can be calming for babies. A 2018 randomized controlled trial looked at how 40 one-month-old babies with gas pains responded to white noise played at 55 decibels. It found that babies who listened to white noise slept significantly more, and cried significantly less, than babies who were swung.
However, medical experts don’t know exactly how much white noise, and at what volume, is safe for babies’ delicate ears. The existing research on infants is sparse, and most of the research on harmful noise has been conducted on adults. According to the World Health Organization, hospitals shouldn’t exceed 40 decibels at night, and 30 decibels during the day. Long-term exposure in adults to noise exceeding 65 decibels has been correlated with heart disease. And according to the CDC, noise exposure in adults of 80 to 85 decibels for over 2 hours can damage hearing.
Pediatric audiologists urge caution when using white noise machines with babies. A 2014 study published in the AAP’s official journal, Pediatrics, looked at 14 white noise machines made for infants and relied upon a 50-decibel noise limit suggested by two small scientific reviews of the few studies related to infants and noise, one published in 1999, the other in 2000. It found that all 14 devices exceeded the 50-decibel limit for babies in nurseries when placed about a foot (30 centimeters) away from the baby, concluding that if parents use white noise machines, they should always be placed at the lowest possible level, and placed at least 7 feet away from the baby’s bed—never in the crib or on the crib rail.
The Snoo’s white noise machine is in the crib, right beneath where a parent may lay their baby’s head (babies can be placed in the opposite direction in the Snoo if they want their baby’s head to be farther away from the speaker). And its noise, even at its lowest level, exceeds the limits recommended by the study published in the AAP’s journal Pediatrics if played for long periods of time. Chantal Laroche, PhD, a professor of audiology and speech language pathology at the University of Ottawa, says, “50 dBA averaged over an hour would be a safe limit and should not induce any degree of hearing loss.” (The Snoo’s lowest level is louder than this, playing white noise at 65 to 70 decibels). Again, limited research on the impact of noise on babies makes it difficult to know how much sound a baby can safely be exposed to. “Not knowing well the effects of noise on the hearing of young babies, it is better to be more careful than not enough. The precautionary principle should take precedence,” says Laroche.
Karp notes that the white noise, on any level, isn’t supposed to be played 24/7, as babies need at least several hours a day to listen to normal, day-to-day sounds of their parents’ voices and the general noise of a home. If using the Snoo, parents can do this either by turning it completely off, or letting their baby hang out outside the Snoo.
To be safe and protect their baby’s ears, parents electing to use white noise machines should play it at its lowest level, and keep it off whenever possible, so that the baby can hear their parents’ voices and train themselves to fall asleep without the white noise, according to What to Expect, the medically reviewed website from the creator of the original "What to Expect" book series.
Questions About the Swaddle
According to the Snoo user guide, babies should be strapped into the Snoo sack whenever they are in the Snoo. “If you’re swaddling babies, and you’re rocking them, you better secure them in place so that they can’t go to an unsafe position,” says Karp. “And that’s one of the key benefits of Snoo.” The Snoo sack prevents the baby from shifting onto their side or stomach and risking suffocation when they’re in the Snoo while it is moving. To a certain extent, this is in keeping with safe infant sleeping practices, which dictate that a newborn must be placed to sleep on their back, as placing a young baby to sleep on their stomach or side is a leading risk factor of SUID—sudden unexpected infant death. The Snoo is designed to be used for six months, after which a baby is supposed to be transitioned out of the Snoo and into another crib.
But some experts say that swaddling a baby, which is effectively what the Snoo Sleep Sack does, is not appropriate after three to four months, as it can be unsafe and have negative developmental and health effects once the infant is a little older.
“It’s recommended in the empirical literature and by pediatricians that as soon as the baby is able to roll, which generally happens around three to four months, they should abandon the swaddle altogether,” says Wendy Hall, PhD, a professor emeritus in the School of Nursing at the University of British Columbia whose research focuses on infant sleep. “The American Academy of Pediatrics recommends putting an infant on their back to sleep, but if the infant independently repositions him or herself by rolling onto their tummy, it’s safe and desirable to allow that.”
Swaddling in a sack that is secured into the Snoo is a practice that, while not directly addressed in American Academy of Pediatrics guidelines, would contradict recommendations on allowing a child to roll over when they are able to on their own. “Strapping a baby to a mattress via swaddle, or any device, is not consistent with AAP recommendations,” says Lori Feldman-Winter, MD, a professor of pediatrics at Cooper Medical School of Rowan University and a member of the AAP Task Force on SIDS (or sudden infant death syndrome).
Since active use of the Snoo (with the motion and white noise on) requires that a baby is strapped into the Snoo sack, this means that if parents follow AAP recommendations, they’re getting as little as three months of Snoo use before the baby must be transitioned into another crib.
When I asked Karp about the concerns raised by experts we talked to with keeping babies swaddled longer, he disagreed that it was an issue. “That’s a misunderstanding on their part, because the reason we stop swaddling at two to three months is because we don’t want babies rolling over swaddled,” he says. “Because that raises the risk of infant sleep death. But if the baby is secured as they are in Snoo, there’s no risk of rolling over.”
But the risk from rolling over is not the primary concern raised by many of the experts interviewed. We primarily heard about developmental concerns (the product falls under the government’s bassinet standard and conforms to those mandatory safety rules). According to Violet Giannone, a nurse, pediatric sleep consultant, and the author of the book "Baby Sleep Training in 7 Days," babies also need to be able to move around a bit. “When a baby is forced to remain on their back—which is essentially what the Snoo is doing—this can cause some developmental delays,” she says. Babies practice their milestones in their cribs or bassinets, in large part because they spend so much time there, she says. Because babies are strapped into the Snoo without freedom of movement, they’re inhibited from practicing those milestones. “With the Snoo the baby is not able to practice one of the very first few milestones—rolling. Even if they happen to practice it outside of the crib, they are not getting enough practice time, which can cause a domino effect in delays in milestones.”
Rosemary Horne, a professor of pediatrics at Monash University in Melbourne, Australia, whose research focuses on pediatric sleep problems, including SIDS, says swaddling for too long can negatively affect a baby’s physical development. “Swaddling is often used to suppress startle reflexes in young babies, but the continued use of such a restrictive swaddle may impair normal development of the babies’ movements of their arms and hands,” she says. Happiest Baby has guidelines on how parents can remove their baby’s arms from the Snoo sack at 4 to 5 months, if desired, though Horne says “it is recommended that the arms of babies are left unswaddled from 3 to 4 months of age.”
Susan Klemm, an occupational therapist whose work focuses on infants’ head shape and developmental issues, and her colleague Stacy Conder, a physical therapist, own an infant and childhood physical and occupational therapy practice in Charlotte, North Carolina. Klemm and Conder say they’ve frequently discussed head shape and developmental delays with the SNOO with pediatricians and other pediatric therapists, who share similar concerns.
They’ve written about how the Snoo can exacerbate head shape issues in infants already prone to them, and agree with Giannone and Hall, both of whom say that the Snoo can in some cases lead to developmental and physical delays in newborns. “When repositioning during sleep is impeded, rolling when awake can be delayed, which can lead to delayed crawling and, perhaps most important, exploration of the environment,” Klemm and Conder said. “Unfortunately we frequently see infants whose development and/or head shape are negatively affected by restrictive sleep positioners, including the Snoo.”
Such head shape issues include plagiocephaly, also known as flat head, in which a newborn’s head is slightly flat and asymmetrical on one side. Though the issue is sometimes congenital, most cases fall into the category of “positional plagiocephaly,” which can be caused by putting a baby in the same position—such as on their back—day after day during the first 12 weeks of life. This doesn’t only occur in the Snoo, and the issue is relatively common, says Giannone. Plagiocephaly has become more common since the anti-SIDS “Back to Sleep” campaign launched in 1992, according to the AAP. And though flat head is straightforward to treat, in rare cases, untreated plagiocephaly can lead to chewing problems, vision issues, and facial abnormalities, according to the American Association of Neurological Surgeons.
Babies who “practice tummy time” and sleep 14 hours or so in the Snoo, with the remainder spent elsewhere (such as in their parents’ arms or in a baby carrier) are less likely to experience developmental delays and flat head than babies who spend 18 daily hours of sleep in the same position without that crucial tummy time, says Giannone. But because babies often roll for the first time at night when they are alone in their own space, parents may miss that important milestone and keep babies in the Snoo longer than they should, she says. Parents might miss these early signs if a baby is in daycare, too.
Consumer Reports advises parents and caregivers that they can let their baby sleep for short stretches in an infant carrier or car seat, if these products are used properly and the baby is positioned as directed by the manufacturer’s instructions. Just don’t over-rely on them, says William Wallace, CR’s associate director of safety policy. “Infant carriers and car seats are meant for transit, and should not be used as a substitute for a safe sleep environment. CR recommends that parents and caregivers should move their baby to a crib, bassinet, or play yard if the baby is still sleeping once they arrive at their destination,” he says.
Karp says there is no more risk of developmental delays like flat head from the Snoo than from any other baby bed. “Babies in Snoo have the full range of motion of the neck—to turn the head fully to the right or left. This is exactly the same as for babies who sleep in any other baby bed,” he says. “Babies aren’t exercising during sleep—they are sleeping.”
The AAP recommends that babies who can roll over on their own be removed from their swaddle and given the freedom to roll. Parents who elect to use the Snoo can help keep their child with the freedom to develop at their own pace by moving their child into a new bassinet as soon as they show signs of rolling. Some parents may elect to use the weaning feature for a couple of weeks before transitioning the child out of the Snoo. To ensure that parents don’t miss those early milestones, parents can give their baby lots of time outside the Snoo in a safe area, under careful supervision, where they can wiggle, roll, and explore.
Digital Privacy and the Snoo
In 2019, the cybersecurity firm Red Balloon found a concerning digital vulnerability in the Snoo: An attacker on the same WiFi network as the Snoo could theoretically access, and control, the Snoo remotely. The researchers were able to violently rock the Snoo and play loud noise, up to 113 decibels. Red Balloon alerted Happiest Baby of the vulnerabilities; Happiest Baby quickly patched the vulnerability and rolled it out to all units. “This is done automatically, so even older units are patched as soon as the minute they connect to WiFi,” says Karp. No real-life attacks on the Snoo have been reported.
Joe Carrigan, a senior security engineer at Johns Hopkins Institute of Assured Autonomy, says he’s “pretty pleased” with the Snoo’s overall device security, including its ability to operate well without WiFi, and its assurance in its data policy that it won’t sell data to marketers (data collected by wearables and smart devices like the Snoo aren’t protected by HIPAA). “It seems to me like this system is probably more secure than most,” he says. However, privacy policies can change, so a good privacy policy now can change at a later date. This is a concern shared with all connected devices and online services, not just the Snoo.
Though the risk of hacking is low, those who are concerned about their Snoo being hacked can disconnect it from WiFi. The device retains most of its functionality without WiFi access, inhibiting parents primarily from controlling the device from their phone app and viewing their baby’s “sleep report.” Instead, the caregiver can operate the Snoo from the controls on the product’s front. Conversely, having careful data security on the Snoo’s home WiFi system can mitigate any additional risk, if parents wish to keep their bassinet connected.
Weaning Your Baby Off the Snoo
Richter moved her baby out of the Snoo at three months. “Transition was actually fine because he clearly wanted more space to move around,” she says. “We always had an additional white noise machine, which is crucial.” He was very happy in his new crib, she says.
However, according to Giannone and some parents on various online forums, some babies become so dependent upon their Snoo for sleep that it can be difficult to “wean” them off its rocking and white noise once they’ve outgrown it. “I work with so many families that just want their baby to sleep after being transitioned out of the Snoo—they’re having a really hard time sleeping and settling,” says Giannone. “I don’t think parents are aware of what they’re setting themselves up for, with not allowing the baby to learn to sleep independently.” Not every baby has issues transitioning out of the Snoo, she says, but “the majority that I work with have these troubles.” Hall says that six months of early life spent consistently in the SNOO, plus up to two years of exposure to the SNOObear white noise machine, “could lead to a reliance on [white noise] for sleeping.”
This is despite the Snoo’s weaning feature, which is meant to help ease the baby’s transition from the Snoo to a crib. A week or two before before a baby is ready to move on from the Snoo, parents turn on “weaning mode,” which doesn’t rock at the blue, baseline level, though it does play white noise. If a baby cries, though, the Snoo responds with some rocking until the baby stops crying, at which point it stops moving and sticks with the white noise. Happiest Baby recommends Snoo users continue using the white noise until the baby is up to 2 years old, which may explain why I recently encountered a young couple pushing a stroller that made a very loud, somewhat jarring shushing noise when they passed by me.
What to Expect notes that babies can become dependent on white noise, which can present issues if, for whatever reason, white noise isn’t available. In such cases, it may be necessary to first wean the baby off the rocking, then the white noise, by gradually lowering the sound on your white noise machine over the course of a couple of weeks until it’s off, according to Karp.
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