Infant sleep is an act of

sleeping Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain Sensory nervous system, sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with th ...

by an

infant In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...

or a newborn. It differs significantly from

sleep Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain Sensory nervous system, sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with th ...

during adulthood. Unlike in adults, sleep early in infancy initially does not follow a

circadian rhythm A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the env ...

. Infant sleep also appears to have two main modes - active, associated with movement, and quiet, associated with stillness - exhibiting distinct neurological firing patterns. Sleep duration is also shorter. As the infant ages, sleep begins to follow a Circadian rhythm and sleep duration increases. Infants

nap A nap is a short period of sleep, typically taken during daytime hours as an adjunct to the usual nocturnal sleep period. Naps are most often taken as a response to Somnolence, drowsiness during waking hours or as a means to supplement before ...

frequently. Infants are also particularly vulnerable during sleep; they are prone to suffocation and

SIDS Sudden infant death syndrome (SIDS), sometimes known as cot death or crib death, is the sudden unexplained death of a child of less than one year of age. Diagnosis requires that the death remain unexplained even after a thorough autopsy and ...

. As a result, "safe" sleep techniques have been the subject of several public health campaigns. Infant sleep practices vary widely between cultures and over history; historically infants would sleep on the ground with their parents. In many modern cultures, infants sleep in a variety of types of

infant bed An infant bed (commonly called a cot in British English, and, in American English, a crib, or far less commonly, stock) is a small bed especially for infants and very young children. Infant beds are a historically recent development intended to ...

s or share a bed with parents. Infant sleep disturbance is common, and even normal infant sleep patterns can cause considerable disruption to parents' sleep. File:Baby Gurr (4245984654).jpg, Swaddled infant sleeping in a

Moses basket A bassinet, bassinette, or cradle is a bed specifically for babies from birth to about four months. Bassinets are generally designed to work with fixed legs or caster wheels, while cradles are generally designed to provide a rocking or gliding ...

. The infant is on his back as per safe sleep recommendations. File:Day Nursery at Tottenham, London, England, 1940 D459.jpg, An infant sleeping in 1940. The use of pillows and blankets is no longer recommended as these can inadvertently cause suffocation. File:Baby in a hammock with mother in a hut in Laos.jpg, Baby sleeps in a hammock in a hut in Laos. File:Woman with sleeping baby on her back Gambia.jpg, Infants frequently sleep whilst being worn.

Normal infant sleep

In the first week of life, infants will sleep during both the day and night and will wake to feed. Sleep cycle duration is usually short, from 2–4 hours. Over the first two weeks, infants average 16–18 hours of sleep daily.

Circadian rhythm A circadian rhythm (), or circadian cycle, is a natural oscillation that repeats roughly every 24 hours. Circadian rhythms can refer to any process that originates within an organism (i.e., Endogeny (biology), endogenous) and responds to the env ...

has not yet been established and infants sleep during the night and day equally. In the first month of life, 95% of infants will wake during the night. At around 2 months, a day-night pattern begins to gradually develop. At around 3 months, sleep cycle may increase to 3–6 hours, and the majority of infants will still wake in the night to feed. By 4 months, the average infant sleeps 14 hours a day (including naps), but this amount can vary considerably. By 8 months, most infants continue to wake during the night, though a majority are able to fall back asleep without parental involvement. At 9 months, only a third of infants sleep through the night without waking. Daytime sleeping (naps) generally doesn't cease until 3 to 5 years of age. Infant sleep in the first year can be categorised into active sleep (AS) and quiet sleep (QS). Active sleep is similar to the adult REM sleep in that it is characterised by eye and other kinds of movement; however, unlike adults in REM, infants tend to enter AS at the beginning of their sleep cycle, as opposed to the end of it like REM in adults. Infants spend about half their time in AS/REM and half in QS, a much higher proportion than adults, who only spend about a quarter of their time in REM. It's hypothesised this difference in sleep pattern is related to the shorter sleep cycles and more frequent waking of infants. By 3 months infants become more likely to enter quiet sleep (or NREM, not-REM) at the beginning of their sleep cycle. After 3 months, infants tend to alternate between AS/QS for 50 minutes duration, as opposed to the longer cycle in adult sleep (90 minutes). Sleep cycle duration starts to resemble adult sleep more at 6 months, but doesn't fully resemble adult sleep until around 3 years old, which is generally around the time napping ceases as well. Frequent night waking and the short sleep cycle in infants is thought to be adaptive. Because infants have small stomachs and are undergoing rapid growth, they need to eat very frequently in order to get enough nutrition. Frequent night awakenings are also protective against SIDS. {{Citation , last=Ramirez , first=Jan-Marino , title=Sudden Infant Death Syndrome, Sleep, and the Physiology and Pathophysiology of the Respiratory Network , date=2018 , url=http://www.ncbi.nlm.nih.gov/books/NBK513387/ , work=SIDS Sudden Infant and Early Childhood Death: The Past, the Present and the Future , editor-last=Duncan , editor-first=Jhodie R. , access-date=2023-12-22 , place=Adelaide (AU) , publisher=University of Adelaide Press , isbn=978-1-925261-67-7 , pmid=30035952 , last2=Ramirez , first2=Sanja C. , last3=Anderson , first3=Tatiana M. , editor2-last=Byard , editor2-first=Roger W.

References

Infancy Sleep