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SPECIAL ISSUE ARTICLE
Newborn Sleep: Patterns,
Interventions, and Outcomes
Theodore V. De Beritto, MD, MS
ABSTRACT
Sleep is a necessary function of life. Fetuses and neonates spend most of their day
sleeping, making it paramount to place emphasis on adequate and optimal sleep. As the
current body of literature continues to expand, we have increased our understanding
of sleep and its role in development. Sleep disturbances, particularly early in life can af-
fect all aspects of health such as neurological development, emotional well-being, and
overall growth. This article aims to provide a primer on sleep development from fetal life
into the neonatal period, discuss sleep in both the home and hospital settings, explore
the tools used to measure sleep, and review common interventions applied to those in-
fants experiencing poor sleep. Lastly, there is a mention of long-term outcomes and
how early recognition and implementation of measures could help to improve overall
growth and development throughout childhood. [Pediatr Ann. 2020;49(2):e82-e87.]
Over the past few decades, there
has been an increased focus and
growing number of studies that
implicate the importance of sleep on
newborn and infant health. Sleep is an
essential part of life and is a necessary
function of proper development. As the
literature expands, we have increased
our understanding of sleep, particularly
as it pertains to growth, neurological de-
velopment, and emotional well-being.
Sleep deprivation or disturbances in
sleep during early development can lead
to poor overall health, decreased emo-
tional regulation, poor decision-making,
inattention, increased adiposity, and
decreases in academic performance.1
These findings were first noted in adults,
but recent studies also suggest that signs
of these deficiencies can be seen as ear-
ly as the neonatal period.2 Attention to
these details is important, as early sleep
intervention can have lasting positive ef-
fects on development.
SLEEP DEVELOPMENT
Sleep has been defined as a revers-
ible state of minimal interaction and de-
creased responsiveness with the environ-
ment.3 Although it is a physical decrease
in responsiveness, it can be argued that
it is a time of enhanced neurological
function and physiologic activity. Sleep
is composed of four primary stages
including the awake state, transitional
sleep, active sleep, and quiet sleep.
Each category carries a different level
of wakefulness and is defined by a pro-
gression of changes regarding physical
characteristics (Table 1).
In the awake state, eyes are open
with regular or slowing eye move-
ments, the body continues to have nor-
mal movements with an increase in
startling, there continues to be irregular
respirations, an electroencephalogram
(EEG) will demonstrate a continuous
medium voltage pattern, and an am-
plitude integrated EEG (aEEG) will
show a narrow bandwidth. In the tran-
sitional state, eye movements begin to
slow with lengthened periods of eye
closing, both motor and facial activity
will start to decrease (although vocal-
ization begins to increase), respirations
become more regular, and the EEG will
show a continuous high voltage pattern
while an aEEG will show a variable
bandwidth. As sleep progresses to the
active state, eyes will be closed with
rapid eye movement (REM). Motor
and facial activity will be limited with
occasional slow twitches and bursts of
vocalization, and respirations will be ir-
regular. The EEG in this state will show
continuous low voltage and the aEEG
will have a narrow bandwidth. Lastly,
in the quiet sleep phase, eyes will be
closed with relatively no eye or body
movements. Facial expressions will be
limited, and the infant will have occa-
sional sighs. The EEG in this state will
Theodore V. De Beritto, MD, MS, is a Neonatal-Perinatal Medicine Fellow, Division of Neonatology,
Department of Pediatrics, LAC+USC Medical Center, Keck School of Medicine, University of Southern
California.
Address correspondence to Theodore V. De Beritto, MD, MS, Division of Neonatology, Department of
Pediatrics, LAC+USC Medical Center, Keck School of Medicine, University of Southern California, 1200
North State Street, IRD Building, Room #820, Los Angeles, CA 90033; email: tdeberitto@chla.usc.edu.
Disclosure: The author has no relevant nancial relationships to disclose.
doi:10.3928/19382359-20200122-01
PEDIATRIC ANNALS • Vol. 49, No. 2, 2020 e83
SPECIAL ISSUE ARTICLE
be slow, but have a wide range of volt-
age, and the aEEG will show a wide
bandwidth.4
It is important to recognize that as
an infant develops, these sleep states
continuously change. For instance, the
number of sleep cycles during the day-
time will decrease as an infant gets old-
er.4 Other alterations in sleep that can
vary with age include lengthening of
the interval between sleep, decreased
REM activity, decreased active sleep,
increased quiet sleep, and shortening
of the time spent in the transitional
sleep stage.5 The sections to follow
will outline the changes in sleep based
on key milestones in development.
FETAL SLEEP PATTERNS
Although simple movement in the
fetus can be detected as early as 7 to
8 weeks postmenstrual age, conscious
movement and distinct patterns of mo-
tion are not noted until 15 weeks ges-
tation. Even later are sleep states, as
these are not present until the second
half of gestation. During this latter
half of pregnancy, it is speculated that
the cyclical rhythm of fetal wake and
sleep patterns are guided by the pla-
cental transfer of maternal melatonin.6
Regarding the amount of time spent
sleeping, in fetal lamb studies, sub-
jects were noted to be in both active
and quiet sleep for the majority of
gestation with only occasional peri-
ods of wakefulness. This observation
is largely due to environmental factors
in-utero that promote sleep, includ-
ing both warmth and various chemi-
cals (prostaglandin E2, pregnanolone,
adenosine, and allopregnanolone).
Breathing and body movements once
thought to be a component of the
awake state, occur during sleep states
and are important in strengthening the
respiratory muscles responsible for ex-
trauterine life.
Episodes of true wakefulness are
rarely observed in-utero, but when
they occur, they are defined as periods
of vigorous activity with increases in
heart rate and swallowing. As the fe-
tus approaches 28 weeks of gestation,
awake states will occur more frequent-
ly, and distinct activity patterns can be
noted more clearly.7
PRETERM AND TERM SLEEP
PATTERNS
Similar to the fetus, a premature
neonate can have clear periods of ac-
tive and quiet sleep that can be de-
tected as early as 25 to 27 weeks of
gestation. Postnatally, these infants
can spend upward of 90% of their time
sleeping, compared to their full-term
counterparts who sleep only about
70% of the time.7 The key difference
with age is the amount of time spent
in active sleep with REM activity. A
premature infant will spend about 80%
of their time in active sleep, whereas a
full-term infant will spend most of the
time in the quiet sleep phase. Although
the term baby spends less time in the
active sleep phase, they experience
significantly more REM activity when
TABLE 1.
Sleep State Characteristics
Sleep State Characteristics
Awake Eyes: open with rapid or slow eye movements
Motor: rapid startles with normal movements
Facial movements: frowning, smiling, crying, grimacing (with vocalization)
Respirations: irregular
EEG: continuous, medium voltage (70-100 mcV)
aEEG: narrow bandwidth
Transitional
sleep
Eyes: periods of opening and closing, slow eye movement
Motor: slow startles with minimal movements
Facial activity: grimacing, intermittent sucking (with increased vocalization)
Respirations: regular
EEG: continuous, high voltage (100-200 mcV)
aEEG: variable bandwidth
Active
sleep
Eyes: closed with rapid eye movements
Motor: low tone with small, slow twitches
Facial movements: frowning, smiling (with bursts of sucking and vocalization)
Respirations: irregular
EEG: continuous, low voltage (30-70 mcV)
aEEG: narrow bandwidth
Quiet sleep Eyes: closed with no eye movements
Motor: minimal to no movement
Facial movements: rhythmic mouth movement (with occasional sighs)
Respirations: slow and regular
EEG: slow, medium to high voltage (30-200 mcV)
aEEG: wide bandwidth
Abbreviations: aEEG, amplitude integrated EEG; EEG, electroencephalogram.
Adapted from Anders et al.7 and Werth et al.12
e84 Copyright © SLACK Incorporated
SPECIAL ISSUE ARTICLE
compared to the preterm infant. This
indicates better organization of the ac-
tive sleep phase and a noted overall ma-
turity of sleep-wake activity patterns
that occurs with age.8 Low or frag-
mented REM activity is often found in
neonates with developmental delays.
Infants with higher medical risk scores
often have less REM activity during
their active sleep phases. These same
infants have increased fussiness and
longer periods of crying.9
Once a premature infant is correct-
ed to term gestational age, they can ap-
preciate sleep-wake cycles similar to
full-term neonates. Extremely prema-
ture neonates have in fact been noted to
mature their sleep-wake cycles sooner
than their term counterparts. Through-
out the first few months of life, pre-
mature neonates will have longer sleep
durations during the day and night as
well as have an increase in number of
nighttime awakenings when compared
to term babies. At age 6 months, infants
born prematurely have been noted to
be noisy breathers while sleeping and
will also have an increase in number
of apneas or hypopneas. Some studies
suggest upward of 80% of premature
neonates will experience one or more
apneic or hypopneic events per hour.10
This number, however, decreases with
age and seldom requires intervention.
SLEEP IN THE HOSPITAL SETTING
Infants in the neonatal intensive
care unit (NICU) are subject to several
issues contributing to poor sleep. This
is compounded by the fact that pre-
mature infants and those with certain
diseases are at an increased risk for
abnormal neurological development
(Table 2). Over the past decade there
has been an increase in literature sug-
gesting that sleep disruption caused by
even routine handling of neonates can
lead to poor brain maturation.11
In the NICU, several components
of care can contribute to sleep dis-
turbances. These include frequent
interventions (laboratory testing or
procedures), pharmacologic treat-
ment (sedation or antiepileptic medi-
cations), loud or disruptive ambient
noise, abnormal day-night cycles, and
bright lighting.
One study11 observed neonates for
a 4-hour block of sleep that found that
only 50% of these patients were able
to complete a full sleep-wake cycle
before being disturbed for care. Dur-
ing provider contact, 57% of these
patients had some level of awakening.
Often these awakenings were associat-
ed with desaturations or apneic events
and potential further arousal with any
needed intervention.11 Although there
have not been any studies that associ-
ate sleep disturbances with the need
for respiratory support, it is important
to recognize the potential for negative
impact on sleep.
TOOLS FOR MEASURING SLEEP
Observational Methods
There are many tools for the mea-
surement of sleep that range from ob-
servational, which is least invasive, to
more technology-dependent invasive
methods. The clinical assessments that
are least invasive include assessment
of heart rate and behavioral classifica-
tion of sleep. Each are well studied,
reliable, and do not need any techno-
logical support. Furthermore, they do
not cause any long-term damage and
can be used as an assessment method
for a significant length of time.
Heart rate assessment or monitor-
ing of heart rate variability has been
studied as a marker for neonatal sleep.
This method is more commonly used
in both adults and pediatrics to assess
disease-state progression. In this case,
an assessment of beat-to-beat variabil-
ity is conducted. Any dynamic changes
in slowing or increase in heart rate re-
flects the autonomic nervous system.
The interaction between neural inputs
of the parasympathetic and sympa-
thetic systems guide these changes
and variabilities in heart rate. After
about 30 weeks corrected gestational
age, these heart rate variability moni-
tors can interpret slowing as it relates
to sleep and quickening as is associ-
ated with periods of wakefulness.12
Although neonatal sleep is best
assessed through technology, inter-
pretation of a neonate’s physical ex-
amination findings and behavioral
patterns can help to determine which
sleep state they are in. As described in
Table 1, each sleep state has several
distinguishable motor movements.
Most commonly eye movements
(opening and closing), vocalization
(no vocalization to mild sighing),
and motor coordination (from normal
movements to startles or small jerks)
can be used, as each characteristic has
a pattern corresponding to a distinct
sleep state. It is important to be mind-
ful of respirations as well, as respira-
tory rate and quality can also be useful
in classifying sleep.12
Although the gold standard in mea-
suring sleep lies with technology and
more invasive monitoring, clinical
observation can be especially useful
in settings where this technology is
not available. In these situations, be-
havioral classification in conjunction
with heart rate variability may be able
to give observers the best estimate of
a neonate’s sleep status.
Technology-Dependent Methods
The more invasive methods of sleep
measurement include aEEG, EEG,
and polysomnography. Each of these
modalities requires a technological
interface and use of probes and moni-
PEDIATRIC ANNALS • Vol. 49, No. 2, 2020 e85
SPECIAL ISSUE ARTICLE
tors to achieve a more comprehensive
assessment of an infant’s sleep.
The least invasive is an aEEG. With
this modality, two leads are placed bi-
parietally on the neonate’s head (each
probe corresponding to the parietal lobe
on that side of the head). The clinician
in this instance can detect the presence
of the sleep-wake cycle at the bedside. A
wide bandwidth corresponds with quiet
sleep, whereas a thin or narrow band-
width will be associated with wakeful-
ness or active sleep. Cyclic variation of
the aEGG can first be seen in neonates
at 26 weeks gestation, and the more tra-
ditional sleep-wake cycle will be seen at
about 31 to 32 weeks of gestation.13
More invasive than aEEG is the tradi-
tional EEG, described in the neurology
literature. In addition to a more in-depth
description of brain function, this mo-
dality allows clinicians to observe brain
and central nervous system maturation
over time. Although its reliability begins
only after a neonate reaches 30 weeks
corrected gestation, it is a much more
comprehensive look at the sleep-wake
cycle. However, it is more sensitive to
the dulling effects of pharmacotherapy.14
Finally, polysomnography is the most
complete picture and the current gold
standard when measuring sleep. In ad-
dition to EEG, this modality includes
pulse oximetry, electrooculography,
electrocardiography, and chin electro-
myography. With this technology, the
clinician can measure sleep states, tim-
ing of apnea events, as well as the nature
of the events (central versus obstruc-
tive), ultimately giving a global assess-
ment of an infant’s sleep.15
COMMON INTERVENTIONS
Healthy and normal sleep in new-
borns depends largely on a consistent
routine. Proper management of daytime
and nighttime routines is essential in op-
timizing an infant’s developmental and
physiologic sleep requirements. As this
varies from child to child, it is important
to remain adaptable while also recogniz-
ing issues with sleep and intervening
in a timely manner. Evidence-based in-
terventions that can be implemented in
every setting include light modification,
sound modification, infant massage, and
skin-to-skin contact.
Light modification is a simple and
relatively effortless change that can be
made in every setting, particularly in
the NICU. The benefit can be achieved
through maintaining darkness or creat-
ing a day and night type pattern with the
lighting. Studies demonstrated an asso-
ciation with shorter time to full feeds,
decreased length of stay, and possible
fewer ventilator days.16 An additional
benefit is that with day-night cycled
light pattern, infants develop a routine
and tend to sleep longer in the night pe-
riods versus infants who did not have a
cycled light pattern.17
Sound modification can have tremen-
dous benefits. Infants who are exposed
to excessive stimulation have been
known to suffer from apnea, increased
heart rate, and hearing deficits, thereby
casuing possible speech and language
difficulties in later development.18 A
positive modification in addition to cha-
otic noise reduction would be that of
music therapy. Neonates exposed to mu-
sic have shown improvements in sleep,
feeding, and heart rate stability.19 This
effect is most prominently seen in pre-
term infants; however, all neonates can
benefit from sound reduction and the
bonding that comes from music.
TABLE 2.
Sleep Disruption in Common Neonatal Conditions
Condition Sleep Disruption
Chronic lung
disease
Definition: prolonged ventilator or oxygen support leading to signifi-
cant respiratory disease
Sleep alteration: increased respiratory events (desaturations and apnea),
hypoxia, and respiratory-related arousals during sleep
Congenital heart
disease
Definition: anatomical cardiac deficits that lead to poor oxygenation
and hypoxemia
Sleep alteration: delayed sleep-wake cycle for corrected gestational age
Hypoxic-ischemic
encephalopathy
Definition: disruption of cerebral blood flow leading to potentially poor
neurodevelopmental outcome
Sleep alteration: delayed sleep-wake cycle (progressively worse with
more severe injury)
Inborn errors of
metabolism
Definition: disorders caused by enzyme deficiencies essential to meta-
bolic pathways
Sleep alteration: spectrum of findings from no sleep-wake cycle to
normal cycling, depending on the enzyme deficiency
Neonatal
abstinence
syndrome
Definition: abrupt discontinuation of maternal drug use to the chroni-
cally exposed fetus during pregnancy
Sleep alteration: opiate exposure leads to more active, but fragmented
sleep, and the infant is easily arousable; selective serotonin reuptake
inhibitor exposure leads to more active sleep and increased motor
activity during active sleep
Adapted from Barbeau and Weiss.5
e86 Copyright © SLACK Incorporated
SPECIAL ISSUE ARTICLE
Infant massage is an area of growing
interest. Although there does not seem to
be any direct benefit with regard to neu-
rodevelopmental outcomes, the value of
massage comes with its relative ease of
learning, infant-parental bonding, and
the alterations in sleep patterns. Infants
demonstrate a decrease in sleep latency,
remain asleep longer, and have fewer
nighttime awakenings. Other benefits
include decreased crying, lower pain
scores, and increase in heart rate stabil-
ity. Some studies have suggested an add-
ed importance in the preterm population
with improvement in weight gain and a
decrease in length of NICU stay.20
Lastly, is the well-studied and now
widely adapted use of skin-to-skin con-
tact (SSC). From as little as 1 hour per
day over a 2-week period, benefits seen
with this intervention are both physi-
ologic and physical in nature. Neonates
undergoing SSC had an increase in vi-
tal sign stability with fewer episodes of
bradycardia, higher oxygen saturations,
decreased hypothermia, and decreased
respiratory rates. These infants also
experienced improved overall growth
with associated increases in the rates of
exclusive breast-feeding and decreased
episodes of hypoglycemia. Infant-
parental bonding is also improved, as
studies have demonstrated decreases in
both infant and parental cortisol levels
during times of SSC. Regarding sleep,
neonates who benefited from SSC had
fewer awakenings from sleep as well as
better sleep organization.21
LONGTERM OUTCOMES
Infant sleep is often discussed dur-
ing routine pediatric visits. These con-
versations consist of issues with sleep
latency, short duration of sleep, and
frequent nighttime awakenings.22 The
recognition of these sleep deficiencies
and providing early intervention can
be crucial in preservation of a positive
developmental outcome. Although the
body of literature continues to grow,
there seems to be a positive correlation
between good sleep behavior and neuro-
developmental health.
The effects of poor sleep are mani-
fold and can last throughout childhood.
The deleterious effects can be observed
across many systems, the most promi-
nent being metabolic. Although the
exact causality has not been identified,
infants with abnormal sleep and short-
er nighttime sleep duration were more
likely to be overweight. These same
infants also had the propensity to be
overweight into childhood. This effect
is also compounded further by poor diet
and exercise habits.23
Regarding mental health, studies on
sleep highlight the social-emotional is-
sues with sleep disruption. Infants and
children with later bedtimes and re-
duced nighttime sleep often showed
more issues with separation distress, in-
hibition, anxiety, and depression. These
social-emotional problems were magni-
fied 5 times with just a small reduction
in sleep time, 11 hours per day versus
the average 13 to 14 hours.24 When
studied at age 1 year, infants with lower
sleep quality were predicted to have be-
havioral issues and attention-regulation
problems at age 3 to 4 years, reiterating
the importance of optimal sleep at an
early age.25
CONCLUSION
Sleep is perhaps one of the most es-
sential, but commonly overlooked ele-
ments of newborn growth and develop-
ment. Although there has been a recent
increase in the number of studies pub-
lished on newborn and infant sleep,
much is still left to be explored with fur-
ther research. Evidence suggests that it
is necessary to consider the implications
of poor sleep on long-term outcomes,
and furthermore understand how we can
use markers of sleep disturbance to im-
plement earlier interventions.
As a practitioner working with new-
born and pediatric patients, a few other
variables to recognize are parental edu-
cation level, health literacy, socioeco-
nomic status, and cultural differences
that may influence sleep practice. Fur-
thermore, the emphasis on maternal
health with depression screening, stress-
ing the risks of co-sleeping, and provid-
ing resources to temper parental burnout
are also crucial in creating a positive
sleep environment.26 Being mindful of
interventions and therapies in this way
are not only beneficial in establishing a
thoughtful parent-practitioner relation-
ship, but ultimately contribute positively
to the care of each child.
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