SNOO in Home Settings
For caregivers using SNOO for infants in a home setting.
SNOO in Clinical Settings
For healthcare professionals using SNOO for patients in clinical settings.
The 5 S’s: The Scientific Basis for SNOO Smart Sleeper
The 5 S’s is a framework of five sensations that imitate the baby’s in utero experience. The 5 S’s were first described in Dr. Karp’s 2002 parenting guide, The Happiest Baby on the Block. The book and its video added 3 novel concepts to our understanding of the developmental needs of infants: The 4th Trimester, the Calming Reflex, and the 5 S’s.
The 5 S’s are ways to imitate a baby’s in utero experience: Swaddling (snug holding), the Side/stomach position, Shushing (white noise), Swinging, and Sucking. When done individually or together, these usually quickly soothe crying and induce sleep.*
SNOO Smart Sleeper was created to comfort and lull young infants by providing continuous soothing simultaneously deploying 3 of the 5 S’s.
In 2016, Dr. Karp created SNOO Smart Sleeper. SNOO provides 3 of the 5 S’s (Swaddling, Swinging, Shushing) to comfort and calm infants up to 6 months old.
*Babies should always be placed on the back for sleep.
How SNOO Works
Womb-Like Sensations
Gentle rocking, soothing sound, and swaddling increase baby’s sleep by about 1 hour/night
Secure Swaddling
SNOO provides benefits of swaddling while keeping babies safely positioned on the back, modeling the AAP safe sleep guideline
Responsive Soothing
Fussing prompts an advanced algorithm of 4 incrementally increasing levels of soothing sound and motion, often calming crying in under 1 minute
Sleep Training
SNOO provides continuous sound to reduce infant crying and improve infant sleep.
and promote infant sleep safely and effectively.
Learn More
For more information about the SNOO Smart Sleeper, get in touch with us today.
Frequently Asked Questions
What type of white noise does SNOO use?
The noises that SNOO uses generally fall within the pink spectrum. The baseline volume of the SNOO is ~62 decibels (dB), which can be adjusted down to 55 dB The sounds temporarily rise when the SNOO responds to crying.
White noise is recognized as a calming and sleep-enhancing sensation. In the womb, babies are exposed to multiple noises from maternal physiologic sounds, including the voice of the mother and the constant, rhythmic murmur from blood flow through uterine, umbilical, and placental vessels. (1,2)
1. Smith CV, Satt B, Phelan JP, et al. (1990) “Intrauterine sound levels: Intrapartum assessment with an intrauterine microphone.” Am J of Perinat; 7: 312-315, doi: 10.1055/s-2007-999511.
2. Walker D., Grimwade J., & Wood C. (1971), “Intrauterine noise: A component of the fetal environment. Am J of Obgyn, 09(1):91-5. doi: 10.1016/0002-9378(71)90840-4.
Is the white noise level that SNOO uses safe?
The baseline volume of the SNOO is ~62 decibels (dB), which can be adjusted down to 55 dB, temporarily rising when the SNOO responds to crying.
There are no studies to our knowledge that show that a sound machine negatively impacts a child’s hearing. Similarly, there is no published evidence that supports the need of infants to avoid sound 50-70 dB.
Note: 70 dB is the about level of a mom shushing her baby or singing a lullaby.
In late 2023, the American Academy of Pediatrics (AAP), released a policy statement regarding sound and children. It is noted that particularly loud noise– like when headphones are turned up too loud – can be damaging.
The AAP review noted that white noise machines boost infant sleep and decrease crying. Studies show that white noise in the 70 dB range works best and evidence shows that sleep improves the development of a child’s healthy brain and body.
The review cited a study testing 14 nighttime sound machines. The study found that if the machines were played: all night, at maximum level, 1’ from the child’s ears, some exceed the sound level allowed in the adult industrial workplace (workers exposed to constant sound over 85 dB for 8 hours/day may be at risk of eventual hearing loss). The AAP recommended keeping a baby’s sound exposure (the level heard mixing together the hours of the entire day and night) to a 24-hour average of less than 70dB.
Preventing Excessive Noise Exposure in Infants, Children, and Adolescents Sophie J. Balk, MD, FAAP; Risa E. Bochner, MD, FAAP; Mahindra A. Ramdhanie, AuD, FAAA, CCC-A; Brian K. Reilly, MD, FAAP, FACS; COUNCIL ON ENVIRONMENTAL HEALTH AND CLIMATE CHANGE ; SECTION ON OTOLARYNGOLOGY–HEAD AND NECK SURGERY Pediatrics (2023) 152 (5): e2023063752.
Is swaddling safe?
Swaddling must be done safely, avoiding overheating, loose blankets, and making sure the hips and legs can move without restriction. Nevertheless, there is no evidence that swaddling interferes with developmental milestones. Studies of Mongolian and Native American infants who were routinely swaddled for 6 to 12 months reported no adverse effect on motor development. (1)
1. Manaseki-Holland S, Spier E, Bavuusuren B, Bayandorj T, Sprachman S, Marshall T. Effects of traditional swaddling on development: a randomized controlled trial. Pediatrics. 2010 Dec;126(6):e1485-92. doi: 10.1542/peds.2009-1531. PMID: 21123471.
Two published studies found that swaddling actually reduces SIDS risk when infants sleep on the back. (1,2).
1. Ponsonby AL, Dwyer T, Gibbons LE, Cochrane JA, Wang YG. Factors potentiating the risk of Sudden Infant Death Syndrome associated with the prone position. New England Journal of Medicine. 1993;329:377–822.2.
2. Wilson CA, Taylor BJ, Laing RM, Williams SM, Mitchell EA. Clothing and bedding and its relevance to sudden infant death syndrome: further results from the New Zealand Cot Death Study. Journal of Paediatrics and Child Health. 1994;30:506–12.
Pediatricians discourage swaddling after 2 to 4 months, when babies begin to roll to the stomach. That is because when on the stomach, a swaddled baby may have difficulty lifting his head up and away from the mattress or bulky bedding. Indeed, there are reports of swaddled infant dying when they rolled prone.
Unfortunately, that advice can be difficult for parents to follow because 2-4 months of age is also when many babies experience sleep disruptions (sleep regressions, first cold, growth spurt, etc.) That is where SNOO can be of help.
SNOO’s anchored swaddle, when properly used, reduces the risk of rolling during sleep. The SNOO Sleep Sack has corresponding right and left wings with safety loops designed to be physically secured to the clips – after the baby is wrapped in the sleep sack – keeping the swaddled infant securely and safely positioned on the back during sleep. It contains no belts, straps or foam wedges that have been shown to be hazardous to infants.
SNOO’s swaddle allows parents to easily wrap their baby with arms out, and its unrestrictive design has been certified “hip healthy” by the International Hip Dysplasia Institute.
The SNOO Smart Sleeper bassinet plus the SNOO sleep sack is the only baby bed that is FDA De Novo authorized for keeping sleeping babies safely on the back. Infants who are placed in a supine sleep position are at lower risk of SIDS/SUID. The device is intended for home use by caregivers of infants from birth to 6 months of age, who are not yet able to roll over consistently.
Babies have slept in SNOO for a total of over 600 million hours. The company has not received any reports of a properly swaddled and secured baby rolling to the stomach.
Does SNOO increase risk of plagiocephaly?
The American Academy of Pediatrics recommends sleeping on the back, on a firm flat surface which has been associated with a slightly higher incidence of flat head in any standard baby bassinet or crib. In SNOO babies have full ability to move their heads side to side, 180 degrees. There is no way by which the SNOO would increase the risk of plagiocephaly compared to following the AAP’s recommendation of sleeping on the back in any bed with a firm, flat surface. (1)
1. Mark S. Dias, Thomas Samson, Elias B. Rizk, Lance S. Governale, Joan T. Richtsmeier, SECTION ON NEUROLOGIC SURGERY, SECTION ON PLASTIC AND RECONSTRUCTIVE SURGERY; Identifying the Misshapen Head: Craniosynostosis and Related Disorders. Pediatrics September 2020; 146 (3): e2020015511. 10.1542/peds.2020-015511
Will SNOO prevent SIDS/SUID?
According to the CDC, National Institutes of Health, and American Academy of Pediatrics, infants who are placed in a supine sleep position are at lower risk of SIDS/SUID. In addition, it has been reported that room sharing (not bed sharing), breast feeding, nighttime pacifier use, avoiding smoke, keeping bulky bedding out of the bassinet all are additionally helpful in reducing a baby’s risk of SIDS/SUID. Nevertheless, over the past 20 years, the number of healthy babies who die in their sleep (SIDS/SUID) has remained ~3400/year. (1,2)
SNOO is the only baby bed that is FDA De Novo authorized for keeping sleeping babies safely on the back.
SNOO has been shown to keep babies safely on the back, to prevent rolling into a dangerous position, and to reduce the incidence of bed sharing. However, it has not yet been shown to directly reduce the risk of SIDS/SUID. It is difficult to determine the reduction of rare causes of death, like SUID. To prove it requires the examination of an extremely large and diverse population. And, even then, it is difficult to demonstrate clear SUID reduction because the US has no mandatory SUID reporting mechanism. Therefore, despite keeping babies securely on the back, it is possible that cases of infant fatality in SNOO may have occurred, but never been reported. (1,2)
1. Centers for Disease Control & Prevention, (June 21,2022) “Sudden Unexpected Infant Death and Sudden Infant Death Syndrome”, available at: https://www.cdc.gov/sids/data.htm
2. Rachel Y. Moon, MD, FAAP; Ivan Hand, MD, FAAP; THE TASK FORCE ON SUDDEN INFANT DEATH SYNDROME AND THE COMMITTEE ON FETUS AND NEWBORN “Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment” Pediatrics (2022) 150 (1): e2022057990. https://doi.org/10.1542/peds.2022-057990
Is there research that proves that SNOO adds sleep?
Data on file shows that compared to actigraphy studies, SNOO logs had, on average, 52 more minutes of sleep per night (30-77 min, depending on the month). The longest continuous sleep stretch compared to actigraphy studies on average was 146 more minutes of continuous sleep per night (86-199 min).
One study from Wang et al. 2024, did not show a meaningful difference in infant sleep of SNOO compared to the control group.
Use of actigraphy and/or sleep logs to measure sleep has potential limitations that should be considered when interpreting the data.
How does the SNOO measure sleep?
SNOO measures sleep by adding up the time when the SNOO is running on the Baseline setting. Wake time was defined as anytime SNOO’s levels of sound/motion increased above Baseline or anytime SNOO was paused by a caregiver (e.g., to feed).
What was the FDA’s process to review SNOO?
In 2020, the FDA designated SNOO as a Breakthrough Device with the potential to reduce the risk of infant sleep death (SIDS/SUID) by securing sleeping babies on the back. Over the next two years, Happiest Baby worked with the Agency on assembling data and providing evidence on over 100,000 infants that SNOO is reasonably safe and effective at keeping sleeping babies on the back. In 2023, the FDA granted SNOO De Novo authorization as the first infant bed proven to position babies safely on the back.
What is the distinction between FDA De Novo authorized and FDA approved?
FDA has three regulatory pathways under which medical devices come to market, 510K, DeNovo, or Premarket Approval process, and only one of these pathways may use the word “approved” (premarket approval). SNOO chose the de novo pathway because SNOO is an innovative device of low to moderate risk (i.e., a Class II device) without a similar pre-existing device on the market and therefore is FDA De Novo Authorized.
How is SNOO different from other infant positioners?
Over 10 years ago, it was recognized that infant positioners could be dangerous. They had belts, straps, or foam wedges that created hazards to a sleeping baby.
SNOO is the only infant positioner that the FDA has thoroughly evaluated and granted De Novo authorization as being safe and effective at facilitating back sleeping. SNOO contains no belts, straps, or foam wedges that have been shown to be hazardous to infants. SNOO’s sleep sack and safety clip system is designed to keep a baby safely on the back for all naps and all nights, as recommended by the NIH, CDC, and AAP (1,2)
1. Centers for Disease Control & Prevention, (June 21,2022) “Sudden Unexpected Infant Death and Sudden Infant Death Syndrome”, available at: https://www.cdc.gov/sids/data.htm
2. Rachel Y. Moon, MD, FAAP; Ivan Hand, MD, FAAP; THE TASK FORCE ON SUDDEN INFANT DEATH SYNDROME AND THE COMMITTEE ON FETUS AND NEWBORN “Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment” Pediatrics (2022) 150 (1): e2022057990. https://doi.org/10.1542/peds.2022-057990
Did the FDA rule that infant positioners are unsafe?
Over 10 years ago, it was recognized that infant positioners could be dangerous. They had belts, straps, or foam wedges that created hazards to a sleeping baby.
SNOO is the only infant positioner the FDA has granted De Novo authorization as being safe and effective at facilitating back sleeping. SNOO’s sleep sack and safety clip system is designed to maintain a baby safely on the back for all naps and all nights as recommended by the NIH, CDC, and AAP. SNOO contains no belts, straps or hazardous foam wedges. (1,2)
SNOO meets or exceeds all the safety standards required for bassinets and cribs and has been certified as complying with all federal regulations as required by the Juvenile Products Manufacturers Association.
SNOO has been safely used for more than 600 million hours of infant sleep.
1. Centers for Disease Control & Prevention, (June 21,2022) “Sudden Unexpected Infant Death and Sudden Infant Death Syndrome”, available at: https://www.cdc.gov/sids/data.htm
2. Rachel Y. Moon, MD, FAAP; Ivan Hand, MD, FAAP; THE TASK FORCE ON SUDDEN INFANT DEATH SYNDROME AND THE COMMITTEE ON FETUS AND NEWBORN “Sleep-Related Infant Deaths: Updated 2022 Recommendations for Reducing Infant Deaths in the Sleep Environment” Pediatrics (2022) 150 (1): e2022057990. https://doi.org/10.1542/peds.2022-057990
Does using the SNOO have an impact on breastfeeding or weight gain?
There have been no studies examining the impact of SNOO on breastfeeding or weight gain.
SNOO will not settle crying from discomfort or mid-to-late hunger cues. However, there have been interventions examining the effects of using infant soothing (including 5 S’s) to distinguish between hunger cues and discomfort that results in crying. The SNOO is designed to stop automatically—or “time out”— if crying continues for more than 3 minutes. If crying lasts beyond this period, it is assumed that the baby needs assistance from a caregiver.
Is SNOO being used in babies who have been exposed to substances?
Ponder, cited below, used SNOO with NAS babies.
Survey data published in literature has shown that clinicians have utilized SNOO in substance-exposed infants in hospitals. A quality improvement initiative from UCSF demonstrates that SNOO is feasible to use with the Eat, Sleep, Console model. SNOO is used to help reduce crying and improve the sleep of substance-exposed babies in scores of hospitals. However, to date, there is no data regarding what effect SNOO has on the health outcomes of infants exposed to substances in utero. (1,2,3)
1. Gellasch P, Johnson S, Walsh TA. The Experiences and Perceptions of Neonatal Clinicians When Using a Responsive Bassinet. Adv Neonatal Care. 2023;23(4):E88-E95. doi:10.1097/ANC.
2. Gellasch P, Walsh TA, Geiger S. A descriptive evaluation of time savings and work experience among neonatal clinicians when using a responsive bassinet. J Neonatal Nurs. 2023;29(5):781-785. doi:10.1016/j.jnn.2023.03.0013.
3. Ponder KL, Egesdal C, Kuller 3.J, Joe P. Project Console: a quality improvement initiative for neonatal abstinence syndrome in a children’s hospital level IV neonatal intensive care unit. BMJ Open Qual. 2021;10(2):e001079. doi:10.1136/bmj oq-2020-001079
Does SNOO help with postpartum depression?
Infant sleep patterns, infant crying, and maternal fatigue are strongly associated with a new onset of depressive symptoms in the postpartum period (1)
Targeting disturbed and/or insufficient sleep may be an effective intervention for the prevention of postpartum depression and psychiatric comorbidities (2)
At this time, we are not aware of any published scientific literature reporting on the efficacy of SNOO for postpartum depression.
1. Dennis CL, Ross L. Relationships among infant sleep patterns, maternal fatigue, and development of depressive symptomatology. Birth. 2005 Sep;32(3):187-93. doi: 10.1111/j.0730-7659.2005.00368.x. PMID: 16128972.
2. Sharma, V, Sharkey, K Preventing recurrence of postpartum depression by regulating sleep. 2023 Expert Review of Neurotherapeutics, 23:8, 1-9 DOI: 10.1080/14737175.2023.2237194
When babies use SNOO in the hospital, should they be weaned from SNOO before they go home (particularly for substance exposed babies)?
Over 150 hospitals have SNOO which are used in the care of newborns. In the womb, babies experience constant rumbly sound, (1,2) rocking, and snug holding. This is similar to the sensations they experience in SNOO. Of course, babies are not weaned from the womb rhythms, likewise most hospitals do not wean babies from SNOO prior to discharge.
- Smith CV, Satt B, Phelan JP, et al. (1990) “Intrauterine sound levels: Intrapartum assessment with an intrauterine microphone.” Am J of Perinat; 7: 312-315, doi: 10.1055/s-2007-999511.
- Walker D., Grimwade J., & Wood C. (1971), “Intrauterine noise: A component of the fetal environment. Am J of Obgyn, 09(1):91-5. doi: 10.1016/0002-9378(71)90840-4.
How does SNOO integrate with standard hospital monitoring systems? Can it safely alert staff in case of an emergency?
Lysaught et al. 2023 showed that integration with bedside monitoring was possible without degrading signal quality or producing errors. The SNOO itself does not detect medical emergencies, nor can it collect or transmit data from external monitoring systems. If the App is used with the SNOO (the feasibility of which will depend on the site/context), then healthcare workers could obtain the same information about soothing/crying available to commercial consumers (1)
1. Lysaught S, Erickson L, Marshall J, Feldman K. SSSH: Responsive soothing bassinet feasibility study for infants with congenital heart disease after cardiac surgery. J Pediatr Nurs. 2023 Nov-Dec;73:e125-e133. doi: 10.1016/j.pedn.2023.07.022. Epub 2023 Aug 17. PMID: 37598095.
Could use of SNOO negatively impact bonding times and interactions between parents and an infant?
When awake, parents are encouraged to hold their infants, interact, offer tummy time, etc. SNOO is used during periods of infant sleep. When a baby cries, SNOO will respond with 4 incrementally increasing levels of motion and sound, to help calm the baby and lull them back to sleep. During sleep, the parents need to rest and recover. And, while they sleep the baby experiences the continued womb-like rocking and shushing. There is no evidence to suggest that SNOO negatively impacts critical bonding times or reduces interactions between parents and infants. If the baby cries more than 3 minutes, the bed simply shuts off and the parent is required to meet their baby’s needs.
What clinical indications justify the use of SNOO? Are there specific conditions or scenarios where its use is recommended or contraindicated?
The SNOO Smart Sleeper bassinet plus the SNOO Sleep Sack are FDA De Novo authorized to help the baby stay positioned on the back during sleep. Infants who are placed in a supine sleep position are at a lower risk of SIDS/SUID. The device is intended for home use by caregivers of infants from birth to 6 months of age, who are not yet able to roll over consistently.
“Roll over consistently” means the baby has demonstrated—on multiple occasions—the ability to roll from stomach to back during sleep.
SNOO should not be used if the infant can push up on their hands and knees, or has reached 6 months of age, whichever comes first, or if the infant has any condition that would prevent placement in the supine position.
If there are any questions about whether the back sleeping position and/or SNOO are appropriate, caregivers should consult with their pediatric primary care provider. The SNOO is not clinically indicated as a treatment for any medical or clinical condition.