General considerations

While there are general trends in normal sleep development across the first 2 years of life (and beyond) as expanded upon below, it is important to recognize that some degree of individual variability within these developmental trajectories is to be expected, including in sleep patterns and sleep needs. For example, the definition of “sufficient” sleep not only is based on the number of hours on a chart but also takes the functional context into consideration; for example, does the child awaken spontaneously at the expected time or need to be awakened by a caregiver? When given the opportunity to sleep more, does the child extend sleep beyond the typical duration? Are sleep quantity and quality linked temporally to negative changes in daytime mood and behavior?

Sleep and sleep problems especially in young children, represent a complex amalgam of basic sleep and circadian biology, genetic predispositions, environmental influences (including macro such as neighborhood safety and noise and household overcrowding and micro such as the sleeping space and bedding), family dynamics, parenting practices, child temperament, cultural beliefs, values and practices, family stress including caregiver mental illness, financial challenges and exposure to abuse/neglect and domestic violence, medical issues, and developmental concerns. ^,

There are a number of basic trends in sleep that occur during infancy and beyond that reflect the physiologic/chronobiologic, developmental, and social/environmental changes that are occurring across childhood. These trends may be summarized as the gradual assumption of more adult sleep patterns as children mature:

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  Sleep is the primary activity of the brain during early development; for example, by age 2 years, the average child has spent 9500 hours (approximately 13 months) asleep versus 8000 hours awake, and between 2 and 5 years, the time asleep is equal to the time awake.

  
  
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  There is a gradual decline in the average 24-hour sleep duration from infancy through adolescence, which involves a decrease in both diurnal and nocturnal sleep amounts.

  
  
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  Sleep duration, especially in the first year of life, is reported to be quite variable in large epidemiological studies, although this may reflect variability in caregiver estimates of time in bed rather than actual sleep duration.

  
  
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  After 12 months, there seems to be a tendency for children to settle into and track on a “sleep duration percentile.” For example, a child whose sleep duration is in the 10th percentile is more likely to continue to sleep for relatively lower less hours, similar to what would be seen in regard to growth (height and weight) percentiles.

  
  
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  Cross-cultural studies have suggested that sleep duration in infants and toddlers may also be significantly different across regions around the globe; in general, parent-reported total sleep duration is much lower in predominantly Asian countries versus “Western” countries; this seems to be largely due to later bedtimes in the former areas. This may be in part related to cultural variations in caregiver reporting due to expectations regarding “normal” or “ideal” sleep amounts and sleep practices.

  
  
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  The within-sleep ultradian cycle of sleep stages lengthens from about 50 minutes in the term infant to 90 to 110 minutes in the school-age child. This has clinical significance in that typically a brief arousal or awakening occurs during the night at the termination of each ultradian cycle. As the length of the cycles increases, there is a concomitant decrease in the number of these end-of-cycle arousals (night wakings).

Finally, an appreciation of fundamental principles such as importance of caregiver education about normal developmental changes in sleep as part of “anticipatory guidance,” acknowledgment that many sleep behaviors are learned (and thus may be “taught” by caregivers), and recognition that sleep problems in young children also have a profound impact not only on caregivers, but on other family members is critical to successful prevention and intervention.

Normal sleep patterns, sleep milestones, and behavior: 0 to 24 months

A summary of the normal developmental changes in sleep in the first 2 years of life is presented in Table 4.1 . Additional details regarding specific developmental consideration are included below.

Safe sleep principles

SUID remains the third leading cause of infant mortality in the United States and accounts for more than 3500 deaths annually. It is the leading cause of infant death from 1 to 11 months of age.

SUID is a term that includes three classifications of cause of death of infants under 1 year of age: Sudden infant death (SIDS), infant accidental suffocation and strangulation in bed, and all other unknown causes. Because SUID typically occurs during sleep, in many cases there is not enough known about the circumstances of the death to determine definite cause. SIDS is theorized as a “triple risk model.” Infants with underlying vulnerability (e.g., genetic, neurological) experience an exposure to a trigger event/s (e.g., airflow obstruction or risk factor) during a time that is a vulnerable stage of development of the central nervous system or immune system. The majority of SIDS fatalities occur between ages 1 and 4 months and 90% occur by 6 months of age but infants are considered at risk until 12 months of age.

Following the American Academy of Pediatrics (AAP) “Back to Sleep” campaign in the early 1990s, the number of SIDS-related infant fatalities significantly decreased, but this decline has plateaued since the early 2000s and data shows some increase in the incidence of other crib-related infant deaths (including suffocation, asphyxiation, and entrapment). Therefore, in 2016, the AAP expanded the recommendations to increase attention on a safe sleep environment with goal of reducing the risk of all sleep-related infant deaths including SIDS as well as accidental suffocation and strangulation. ^, The AAP updated their recommendations in 2022 to highlight noninclined sleep surfaces, short-term emergency sleep locations, use of cardboard boxes as a sleep location, bed sharing, substance use, home cardiorespiratory monitors, and tummy time.

These recommendations include the sleep environment (i.e., room sharing without bed sharing with caregivers until at least age 6 months), sleeping position and bedding (reinforcing supine positioning for all sleeping periods on a firm noninclined sleep surface and removal of loose bedding from the infant’s sleep area), and sleep aids (avoidance of all soft objects such as stuffed animals and blankets, and recommendation for the use of a pacifier at sleep onset without a blanket or soft toy attached). Other recommendations to reduce SUIDs risk such as encouraging breastfeeding, up-to-date vaccinations, and limiting maternal exposure to tobacco smoke, alcohol, and illicit drugs as well as secondary smoke exposure are included. ^{, , ,}

Infants with gastroesophageal reflux should follow all recommendations for infant-safe sleep including sleeping supine with head of bed flat. Wedges and positioners are not effective in reducing reflux and are not recommended. Infants receiving nasogastric or orogastric feeds should also follow the AAP recommendations. Exceptions are only potentially applicable for infants with significant anatomical disorders such as type 3 or 4 laryngeal clefts in which risk of death from GERD outweighs risk of SIDS. ^{, ,}

Despite these recommendations, studies suggest that less than half of infants are “always” placed supine and more than one-half of infants share the parental bed at 8 weeks of age. In one study approximately 90% of infants surveyed had hazardous items such as loose bedding or stuffed toys in the sleep space. Certain factors raise the risk for sleep-associated death, including male gender, Black and Native American/Alaska Native race/ethnicity, exposure to cigarette smoke pre- or postnatally, young maternal age (under 20 years), and infants with medical complications such as preterm birth, cardiorespiratory disorders, low birth weight, and neurological concerns. ^{, ,}

The majority of infant safe sleep education is provided at the delivery hospital. Unfortunately, infant safe sleep education and assessment is limited beyond the initial hospitalization at birth. Research shows the majority of parents report receiving information from their infant’s health care provider about supine sleep, but they are less likely to recall education about use of blankets, objects in the crib, or bedsharing. Thus, initiatives to provide thorough safe sleep education at multiple touch points throughout infancy are likely to increase caregiver adherence.

Medical providers have a responsibility to continually assess and guide caregivers toward infant-safe sleep. At times, these conversations can be uncomfortable. Approaching the family with open-ended questions and a nonjudgmental tone is helpful in encouraging an honest discussion. It is also important to understand the family’s reasons for following unsafe sleep practices: they may be unaware of the full scope of recommendations or there may be cultural differences regarding a family’s approach to infant sleep, including definitions of “good parenting” and differences in intergenerational practices in the setting of multiple caregivers. Caregivers may adopt short-term potentially unsafe sleep practices such as cosleeping in order to address a sleep problem such as frequent night wakings, especially in the setting of caregiver sleep deprivation and exhaustion.

In the pediatric hospital setting, it is vital to model infant-safe sleep practices. While studies have found that caregivers replicate the practices they witness in the hospital, research has also demonstrated that safe sleep practices are frequently not used in the inpatient setting. ^, If medical necessity dictates exceptions, this should be specifically discussed with the caregiver as a temporary medical intervention that is only applicable in the hospital setting.

Finally, it is also important to note that many widely available consumer products are incongruent with infant-safe sleep practices. In bed sleepers, pillow-like loungers, incline seats/sleepers, wedges, pacifiers with stuffed animals, etc. attached are all readily available for purchase by well-meaning caregivers. Understandably, many caregivers assume that if these items are being sold in stores, they are safe. In addition, commercial home apnea/cardiorespiratory smart monitors marketed to reduce SIDS are not recommended, as they have not been demonstrated to be effective and may contribute both to parental anxiety or alternatively to laxity about safe sleep recommendations. ^,

Caregiver styles and values

Different caregiver styles can impact a family’s approach to infant sleep practices and the definition of “problem” sleep. In seminal work originally published in the 1960s but widely referenced today, Diana Baumrind defined four basic parenting styles :

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  Authoritarian —These caregivers tend to expect obedience. They set strict rules with consequences. Children are not included in decision making or problem solving and are often punished for noncompliance. These caregivers have high demandingness with low responsiveness.

  
  
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  Authoritative —These caregivers verbalize clear rules and expectations but children are included in problem solving and decision making. Communication is bidirectional from caregiver to child. These caregivers validate the child’s feelings and attempt to avoid personal criticism and shame. High expectations are backed by a supportive and nurturing style. A common term for this approach is “Positive Parenting.”

  
  
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  Permissive —These caregivers are lenient with very few rules, tend to be warm and responsive, and allow children to direct many decisions, but frequently fail to set boundaries, often acting more as “friend” than “parent.” They often avoid setting limits in order to not upset the child. Caregivers in this category may use threats at times but rarely follow through with the stated consequence.

  
  
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  Uninvolved —These caregivers are often more consumed by their own lives and minimally involved with their child/children. They neither set boundaries nor communicate expectations regarding standards. Children often have to manage their day-to-day needs independently. Caregivers may be uninvolved for many reasons, often these are unintentional. Lack of involvement may be secondary to family stress, including financial pressures, and to being overwhelmed by other issues such as mental health problems or substance abuse, inadequate housing, or lack of knowledge about child developmental needs.

More recently described and oft-quoted parenting styles include the overprotective/over intrusive or “helicopter” parent, the strict authoritative with primary goal of raising high achieving children “tiger” parent, and the promoting of physical independence, reasonable risk-taking, with less than currently typical parental oversight, so-called “free range parenting.”

These parenting styles are not mutually exclusive and some families may fluctuate in the approach to caregiving as needs, circumstances, and the age of the child change over time. Caregiving style is also impacted by child-related factors such as the child’s temperament or behavior and the relationship is therefore more accurately described as bidirectional. Thus, family systems theories are important in understanding how each individual member of the family impacts the style, behavior, and outcomes of the others. Parenting styles are also often influenced by incorporation of or reaction to the caregiver style in which the parent was raised; for example, parents from an authoritarian environment may attempt to implement a more responsive and nurturing environment for their own child as a compensatory mechanism, but as a result may fail to set developmentally appropriate limits.

The various caregiver styles described above provide a useful construct when assessing infant/toddler sleep problems. For example, the permissive style caregiver is often unable to set clear and consistent boundaries and limits. These caregivers may describe being afraid of their toddler or infant’s emotional response. They commonly cope by accommodating all the requests the child makes or “walking on egg shells” so as not to set off a tantrum or crying. They often use terms like the child “won’t let me,” “insists,” or “demands.” Some permissive caregivers turn to threats but often do not follow through on the stated consequence. “If you get out of bed one more time I am taking away your teddy bear.” Permissiveness may also be caused by a knowledge deficit about typical child development, as well as the benefits of a nurturing relationship that includes clear boundaries.

The “helicopter” caregiver may worry excessively that their young child isn’t getting the “right” amount of sleep and express concern that far into the future this will negatively impact academic success. This type of parent may purchase and obsessively view the data from the latest infant sleep monitoring products in an effort to reassure themselves that the child does not have any obvious sleep problems. The use of melatonin to “promote better sleep” in a child who does not display any sleep issues is another example of a well-meaning but misguided excessive focus on sleep.

As another example, research shows consistent developmentally appropriate bedtimes and bedtime routines correlate with fewer sleep problems, as well as improvements in a child’s executive function, attention, working memory, and school readiness, among other measures. However, some caregiving styles negatively impact the setting of bedtime routines or schedules. Permissive caregivers frequently allow the child to develop maladaptive sleep onset associations at bedtime, such as prolonged periods of rocking or taking the child on car rides in order to fall asleep; bedtime routines may be elaborate and lengthy and allow for too many choices. These caregivers often try to implement consistent sleep schedules and habits but are commonly inconsistent in following through. They often have a difficult time tolerating any protest behavior from the child during implementation of new sleep routines. The authoritarian caregiver, for example, may determine that 7 pm is bedtime regardless of whether or not the child’s natural sleep onset coincides with the timing of lights out. This may lead to increased bedtime resistance or prolonged time to fall asleep and highly negative bedtime experiences for both child and caregiver. These caregivers may also be less willing to accommodate the child’s sleep needs or even to accept input from their health care practitioner. The uninvolved caregiver, on the other hand, may not have a sleep schedule at all or have minimal involvement in a bedtime routine.

Caregiver mental health issues

Mental health affects how we think, feel, and act and it is important at every stage in life. Mental illnesses are among the most common health conditions in the United States. Sleep disturbances are common when someone is dealing with a mental health disorder and the relationship is inherently bidirectional. Thus, it is imperative that the interviewing process during a sleep evaluation include questions about mental health concerns of caregivers, as well as difficulties initiating and/or maintaining sleep, unrefreshing sleep, or daytime fatigue/sleepiness. Identifying and acknowledging these concerns not only helps to understand what concerns and limitations the caregiver may have in implementing a behavioral treatment plan for their child’s sleep problem but can also highlight any need for social or other support during this process.

Most caregivers know that sleep is important to themselves and their children, and often report that when they get poor sleep it affects their mood, concentration, energy level, diet, and relationships with partners, family, or coworkers, as well as their ability to parent. Evidence supports a critical role of caregiver behaviors in the caregiver-child interaction. Caregivers with children who are poor sleepers tend to be more anxious and depressed. Furthermore, caregiver depression has been shown to be associated with an increased prevalence of children’s sleep problems. For example, a caregiver who is stressed and has limited coping skills for a variety of reasons including mental health issues may inadvertently maintain a sleep problem by failing to enforce appropriate limit setting to avoid precipitating child distress. If a child is resisting bedtime and unable to settle in bed because they want to continue to watch TV or play, the caregiver may then acquiesce to these demands in order to avoid a tantrum or extended crying, leading to a cycle of escalating demands.

Anxiety and depression can interfere with sleep by making it difficult to fall asleep or wake at night and remain awake in an anxious state until morning. An anxious person may not sleep enough and then feel exhausted during the day, with subsequently increasing anxiety about not sleeping well at night, consequent nights. Caregivers with anxiety who also have to address the needs of a child who sleeps poorly may understandably feel unmotivated or unable to take on the challenges of implementing a behavioral plan. Alternatively, they may become overly focused on their infants’ sleep as a compensatory mechanism; for example, one study found that mothers with anxiety disorders were overly involved in infant and toddler bedtime routines (i.e., cosleeping, sleep association), and these behaviors were associated with higher rates of child sleep problems.

When making any plan to treat a childhood sleep disorder, it is important to consider caregiver anxiety and stress. In a clinical setting, oftentimes anxious caregivers present with more questions and concerns and may require both a more gradual approach to and support for changing their child’s sleep behaviors, including more frequent follow-ups and reassurance. In the end, it is also important to recognize if the caregivers’ anxiety is overwhelming and prevents any ability to make changes to their child’s sleep behaviors as this would then involve helping the caregiver navigate what resources they need.

Marital/partner conflict and cohesion: Coparenting challenges

Caregivers with a newborn enter into a relationship in which they must now work together to manage childcare needs and become parents. Transitioning to parenthood can also cause a high level of stress; sleep disturbances such as nighttime awakenings and shorter sleep duration can affect marital relationships. Studies have found that maternal/primary caregiver’s sleep is more often disturbed by children compared with paternal/partner caregiver’s sleep. During the first three years of life, studies have also shown that fathers are often less involved than mothers in bedtime rituals and less likely to get up with the infant/young child during night wakings. Alternatively, other studies have found that when fathers are more involved in monitoring their children’s sleep as well as in their overall care, infants and toddlers display more consolidated sleep patterns. In addition, dividing caregiving tasks between caregivers, in turn, helps mothers/primary caregivers to achieve better sleep and may contribute to less night wakings.

When there is marital (partner) conflict it may lead to difficulty in coordination and cooperation when it comes to managing their child’s sleep. Often times the focus on the child’s sleep problem may be a way to deflect the underlying conflicts at home. This can lead to difficulty in consistent parenting values, responsibilities, and routines. As an example, one parent may actively undermine the other or become overly involved in the child’s life, thus leaving the other parent feeling withdrawn or disconnected. Also, routine bed sharing of the child with one caregiver while the other caregiver is “made” to sleep in a separate room may mask underlying relationship issues. If conflict at home is not addressed first, then it may hinder and impact how each caregiver manages sleep routines and works together to resolve any sleep disruptions that their child is having. Research shows that fathers who report higher marital satisfaction and social support, and lower levels of parenting stress, seem to be more involved in caring for their children at bedtime. ³⁹ Thus, mutual parental involvement and decreased stress may moderate children’s sleep. In contrast, research shows that caregivers with poor sleepers tend to be more anxious and depressed and less happy in their relationship.

Lastly, divorce or separation may significantly influence a child’s sleep. In younger children, there may be an increase in separation anxiety or fear of abandonment by both parents. Sleep routines, schedules, and the type of sleeping arrangement can also vary depending on which household the child is sleeping in. There also may be conflict due to the broadly different parenting styles at each home, leading to a “good cop/bad cop” scenario. Going back and forth between households with different (and sometimes diametrically opposed) sleep rules can be demanding on the child. While sometimes challenging to achieve, studies show that the quality of the relationship between coparents can have a strong influence on the mental and emotional well-being of children, including their sleep. In clinical practice, it not only is challenging to provide a treatment plan that both households can follow through with but can also become disruptive to any progress made in one household if the plan is not followed in the other. The provider can also be caught in the middle of any conflict between households, in which one caregiver’s intention may be to put blame of a child’s sleep disruption due to the other caregiver not following any treatment guidelines. It is important to recognize these conflicts and refer to appropriate support services for the family.

Sibling influence

Bringing home a new sibling can be a joyous and celebratory time but may also bring on some challenges when it comes to figuring out how to manage already existing sleep disruptions in the household (child or caregiver) or bedroom logistics.

Sleep problems may start from the time the separation from mother happens due to childbirth or hospitalization related to pregnancy complications. If the mother was primarily “in charge” of bedtime and the bedtime routine, then is suddenly no longer available at this time, especially unexpectedly, the child(ren) may develop trouble falling asleep or staying asleep with the change in routine and caregiver absence. This may also be manifested by an increase in separation anxiety upon mother’s return for fear that she may leave again.

As the time of arrival of a new baby, routines may be thrown off and any positive sleep changes that had been implemented prior to the birth may be put aside, whether it be from the exhaustion of caring for the newborn or caregiver guilt (feeling they need to give increased attention to the sibling if they are preoccupied with the newborn). Luckily, many toddlers, even after the birth of a sibling, continue on with life with little interest in the newborn. Children who are older are often more interested in a new sibling and may even try to “help” with care of the newborn. Planning ahead in terms of addressing existing sleep concerns and new challenges (e.g., the need for the older sibling to transition to a toddler bed, where the new sibling will sleep in the short-term and eventually, and if they will share a room with the sibling or have their own room) well in advance of the birth (e.g., several months) so that positive behaviors are well-established. Alternatively, these changes could be postponed until the family as a whole has settled in with the new sibling. This also makes any temporary regression in sleep habits easier to anticipate and manage. For example, a young child who is currently bed sharing or room sharing with caregivers may have the reaction that the “new baby took my crib/room” and it is important to acknowledge the legitimacy of these feelings and to anticipate and deal with them in a developmentally appropriate fashion. That being said, new parents of a second child often have concerns about sleep habits and begin anticipating. It is important that new parents continue to try to establish good sleep hygiene in the older child before the arrival of the new sibling. If they plan to transition to a toddler bed, do this with enough time before the arrival of the new sibling. The sibling should have a if there is a plan to work on any behavioral insomnia treatment plan with the older sibling, encourage caregivers to do this in plenty of time prior to the new sibling arrival (1–2 months before).

In households with multiple children, caregivers may also put addressing sleep problems in one child on the back burner so it will not cause disruption to the other siblings’ sleep. Initial attempts at instituting a behavioral intervention, if it results in awakening a sibling, may lead to abandoning the behavioral plan to avoid having the entire family awake during the night. What caregivers may not realize is that siblings often sleep through any noise their brother or sister might make, whether they sleep in a separate bedroom or share one; however, there are certainly circumstances in which the child’s protesting is loud enough to disturb the sibling. If caregiver attention to limit testing behaviors around sleep ends up inadvertently reinforcing negative behavior (i.e., if the child learns that screaming so loud will wake his sibling and he therefore gets a caregiver to sleep with him in order to avoid this). The situation may be helped by explaining the plan to the other sibling and motivating her/him to go back to sleep during the night, negotiating a later bedtime for an older sibling, or temporarily moving them to another room. Caregivers may also use a sibling to help the poor sleeping child to not feel frightened at night by having them sleep in the same room. A sibling should not be used to help overcome fears at night. Often this does not resolve the underlying fears and can act as a temporary “Band-Aid” and issues will start up again. Encouraging parents to continue with stable routines, setting limits at bedtime and during the night, is important even when a sibling is involved.

When dealing with a family that has twins or multiples, this can also add an area of stress when it comes to sleep challenges. More often than not, twins may share a bedroom and if there is one twin that sleeps better than the other, then this adds a layer of difficulty when trying to implement any behavioral interventions as the fear of waking the other twin often defeats any attempts of trying to help resolve the sleep problem. Frequently, twins/multiples can also feed off each other during times when caregivers are trying to set limits around bedtime and during the night leading to more unnecessary behaviors and difficulty for caregivers to follow through with any limits they are trying to set. If necessary, removing one of the twins out of the room temporarily may be the only option in order for the caregiver to help the other twin sleep.

Sleep in alternative care settings

Alternative care settings for young children, including community settings such as foster care, kinship care, and shelters, may contribute to the risk for poor sleep health and sleep disparities. A number of factors combine to create heightened sleep-related vulnerabilities in children in alternative care settings. For example, before entering the child welfare system, children commonly experience a number of known risk factors for sleep-wake dysregulation including poor maternal prenatal health, perinatal risks such as prematurity and drug exposure, poverty, unstable and chaotic home environments, caregiver mental health problems, domestic violence, and child maltreatment. The subsequent abrupt removal from a parent’s care, no matter how unsafe circumstances may be, serves as an additional trauma. These early adverse experiences, particularly if unbuffered by a safe and sensitive caregiving relationship, can set off a cascade of biological stress responses known to give rise to disruptions in the quality and quantity of sleep. In fact, disturbances of sleep are among the most common symptoms of early trauma and do not necessarily subside over time.

Awareness of these vulnerabilities and provision of support services and education to alternative care providers are critical to preventing or mitigating sleep disruptions in these families. Safe and stable home environments and the development of secure attachment to primary caregivers provide the necessary infrastructure for good sleep health, but education regarding developmentally appropriate sleep habits and behavioral approaches to managing sleep problems are also key. This point is deserving of particular emphasis, as greater levels of caregiver-reported sleep disruption in children are associated with more time spent in foster care, a greater number of placements, and higher levels of caregiver distress, in addition to the many established negative outcomes associated with poor sleep health in general.