Infant sleep training

The development of sleep over the first year

During the first year of life, infants spend most of their time in the sleeping state. Assessment of sleep during infancy presents an opportunity to study the impact of sleep on the maturation of the central nervous system (CNS), overall functioning, and future cognitive, psychomotor, and temperament development. Sleep is essential to human life and involves both physiologic and behavioral processes. Sleep not simply as a resting state, but a state that involves intense brain activity. The first year of life is a time of substantial change in the development of both the human brain and sleep. The relationship between the two is vital, as the control of sleep and the sleep-wake cycle are regulated by the CNS.

The long sustained sleep period (LSP) is the period of time that a child sleeps without awaking. The length of this period increases dramatically between the first and second months. Between the ages of three and twenty-one months, LSP plateaus, increasing on average only about 30 minutes. In contrast, a child’s longest self-regulated sleep period (LSRSP) is the period of time where a child, without sleep problems, is able to self-initiate sleep without parental intervention upon waking. This self-regulation, also called ‘’’self-soothing’’’, allows the child to consistently use these skills during the nocturnal period. LSRSP dramatically increases in length over the first 4 months, plateaus, and then steadily increases at 9 months. By about 6 months, most infants can sleep 8 hours or more at night uninterrupted or without parental intervention upon awaking.

In terms of actual numbers, an infant from one to three months of age may sleep sixteen to eighteen hours a day in periods that last from three to four hours. By three months the period of sleep lengthens to about four or five hours, with a decrease in the total sleep time to about fourteen or fifteen hours. At three months, they also start to sleep when it is dark and wake when it is light. By 4 months there are 2 distinct napping periods, mid-morning and late afternoon. By 6 months the longest LSP is 6 hours and occurs during the night. There are two 3-or-more hour naps with a total average sleep time of fourteen hours.

Though sleep is a primarily biological process, it can be treated as a behavior. This means that it can be altered and managed through practice and can be learned by the child. Healthy sleep habits can be established during the first four months to lay a foundation for healthy sleep. These habits typically include sleeping in a crib (instead of a car seat, stroller, or swing), being put down to sleep drowsy but awake, and avoiding negative sleep associations, such as nursing to sleep or using a pacifier to fall asleep, which may be hard to break in the future.

Every child is different and each child’s sleep becomes regular at different ages within a particular range. In the first few months of life, each time the baby is laid down for bed and each time he or she awakens is an opportunity for the infant to learn sleep self-initiation and to fall asleep without excessive external help from their caregiver. Experts say that the ideal bedtime for an infant falls between 6 pm and 8 pm, with the ideal wake-up time falling between 6 am and 7 am. At four months of age, infants typically take hour naps two to three times a day, with the third nap dropped by about 9 months. By 1 year of age, the amount of sleep that most infants get nightly approximates to that of adults.

Good Sleep Conditions

Many parents try to understand, once the baby is asleep, how to keep them sleeping through the night. It is important to have structure in the way a child is put to sleep so that they can establish good sleeping patterns. Researchers have found that babies learn how to fall asleep through a process called operant conditioning, by use of reinforcement. Sleep will reinforce the behaviors that precede it. Regular cues including those mentioned above, such as dimming the lights, singing lullabies, quieting the surrounding environment right before bed or the association of a fixed and specific place for sleep, act as stimuli for the behavior of ‘’self-sustaining sleep’’; that is, sleep that will be triggered by the child him or herself and last through the night. There are additional hypotheses as to what might help and hurt a child in falling asleep and staying asleep. Some researchers believe children who learn to fall asleep on their own have longer sleep cycles as opposed to falling asleep with parental presence. Devices that rock your baby to sleep and devices that provide white noise are commonly marketed as baby sleep aids.

Though no rigorous studies exist, some lay people believe:
As well, comforting children, upon awakening, outside of their beds is associated with poor sleep consolidation. Comforting should take place within the child’s bed area. Parental attention will however act as reinforcement for signaling or calling out to the caregiver if intervention is too long or busy (such as feeding). Attending to the infant upon being signaled should be as short as possible, if the goal is to train the child to put him/herself back to sleep if s/he wakes up in the night. When the caregiver provides intense intervention, the infants’ crying is “rewarded” by the comfort of a parent. The child will deduce that if s/he cries, the parent will provide excessive attention.

Dr Sylvia Bell of Johns Hopkins University reported: by the end of the first year individual differences in crying reflect the history of maternal responsiveness rather than constitutional differences in infant irritability. She also notes: consistency and promptness of maternal response is associated with decline in frequency and duration of infant crying.

Controversies in Sleep Training

A key debate in sleep training revolves around getting the right balance between parental soothing and teaching the baby to self-soothe. Parents who practice attachment parenting think the parent should attend to the baby whenever they cry, and limit tears as much as possible. However, many popular sleep training methods, such as the Ferber Method rely on letting the baby cry it out for a certain number of minutes, so they can learn to self-soothe instead of always relying on the parents to soothe them. The Ferber method has been criticized by some for being harsh, but sleep scientists find it causes no lasting harm to the baby. However, some psychologists say the sleep scientists are failing to take into account the subtle psychological effects of being left alone to cry yourself out: they say: "The fact is that caregivers who habitually respond to the needs of the baby before the baby gets distressed, preventing crying, are more likely to have children who are independent than the opposite. Soothing care is best from the outset. Once patterns of distress get established, it's much harder to change them."

Baby soothing techniques include bouncing, jiggling, rocking baby while sitting in a rocking chair, doing knee bends while holding them, doing comfort feeding, providing them with a pacifier, using a white noise machine or app, swaddling them, skin-to-skin contact, using a bouncer or swing to mechanically rock them, and more. Some parents reject the use of most or all baby soothing techniques under the idea that you should teach a baby to self-soothe. Other parents think having devices such as white noise machines and swings are crucial because they allow the parents' to take breaks and get things done other than just holding their baby.

Other influences on infant sleep

A number of factors have been shown to be associated with problems in sleep consolidation, including a child’s temperament, the degree to which s/he is breast-fed vs. bottle-fed, and his/her activities and sleepiness during the day. Moreover, co-sleeping, which is defined here as sharing a room or bed with parents or siblings in response to an awakening, can be detrimental to sleep consolidation. It is important to note that none of these factors have been directly shown to cause children’s sleep consolidation issues. In terms of infant feeding, breastfeeding has been found to be associated with more waking at night than bottle-fed infants because of the infant’s ability to digest breast milk more quickly than formula. Thus, breast-fed infants have been observed to begin sleeping through the night at a later age than bottle-fed infants: bottle fed infants tend to begin sleeping through the night between 6–8 weeks, while breastfed infants may take until 17 weeks before sleeping through the night. Seventeen weeks of age is still within the first 4–5 months of the infants’ life; therefore, this cannot really be considered a delay in sleep consolidation. There are many benefits to breastfeeding infants. Lastly, temperament also seems to yield correlations with sleep patterns. Researchers believe that infants classified as “difficult,” as well as those who are very sensitive to changes in the environment, tend to have a harder time sleeping through the night. Parents whose infants sleep through the night generally rate their infant’s temperaments more favorably than parents whose infant continue to wake; however, it is hard to determine if a given temperament causes sleep problems or if sleep problems promote specific temperaments or behaviors.