Women’s Health Today

Mother-baby experts (Tracy Cassels, Sarah Ockwell-Smith, Wendy Middlemiss, Kathleen Kendall-Tackett, Helen Stevens and Darcia Narvaez) weigh in to examine what is “normal” infant sleep.

Most new parents complain about lack of sleep, worrying whether their babies have a “sleep problem,” and if what they are experiencing is “normal.” They search online and in books, ask friends and family, or even their doctor, for answers to correct their child’s problematic sleep patterns. And they worry—a lot. 

In our culture there exists an epidemic of parental angst, when parents are repeatedly told that they need to worry, and fear dire consequences if their child doesn’t get enough sleep. Most new parents have little experience of children prior to having their own, so are unaware of what is truly normal when it comes to infant sleep.

We hope to help alleviate parental stress and anxiety simply by explaining what is normal.

So what is “normal”?

My child wakes every hour, all day and night, to feed.

Whether it’s every hour, every two, or even three, parents are often worried when their infant is waking regularly for feedings. This concern is not surprising given the focus on “sleeping through the night” that our culture pushes. But sleeping through the night is not biologically normal, especially for a breastfeeding baby.

At the time of birth, a baby’s stomach can hold only a teaspoonful of milk. He will need to feed frequently to meet the demands for energy that accompany this period of intensive growth. Although the stomach grows relatively quickly, the fat and protein content in human breast milk is much lower than in the milk of other mammals, and thus, infants are required to feed often, resulting in frequent night wakings (Ball, 2003; Ball, 2009).

Why formula is ill suited for nighttime nourishment

Human breast milk, designed for infants who need to feed on cue, day and night, is easily and quickly digested. Formula, however, is typically made from the milk of another species–cows–and is higher in fat, while also containing myriad additives that make it more difficult, and thus slower, to digest. Drinking formula can result in more unnaturally deeper infant sleep from which it is most difficult to arouse to terminate breathing pauses (Butte, Jensen, Moon, Glaze, & Frost Jr., 1992). This is especially true for infants who have a deficient arousal response. Longer spells of stage 3–4 (deep) sleep potentially diminish the infant’s capacity to maintain sufficient oxygen. Even so, formula use does not necessarily provide parents with more sleep overall (Doan, Gardiner, Gay, & Lee, 2007;  Kendall-Tackett, Cong, & Hale, 2011).

Infants whose primary source of energy is breast milk will wake frequently to nurse, something that is essential for the breastfeeding relationship to continue (Ball, 2009). However, regardless of feeding status, many infants wake regularly during the night (Weinraub, Bender, Friedman, Susman, Knoke, Bradley, et al., 2012). Waking through the night is normal and biologically adaptive. In fact, though it is often reported that sleep patterns consolidate in the second year, the pattern differs in breastfed children.

More sleep

Breastfeeding mothers may wake more often, but report greater total sleep. In a study of 6,410 mothers of infants 0 to 12 months old, exclusively breastfeeding mothers reported both more wakings and more total sleep time compared with mixed- or exclusively formula-feeding mothers (Kendall-Tackett et al., 2011). The exclusively breastfeeding mothers reported less daytime fatigue, more energy, less anger and irritability, and lower levels of depressive symptoms. Interestingly, mothers who were both breast and formula-feeding reported fewer hours of sleep than exclusively breastfeeding mothers, and there was no significant difference between the mixed- and formula-feeding mothers on any of the outcome measures. This is important because new mothers are often pushed to supplement to “get more rest.” These results, consistent with the findings of Doan et al. (2007), suggest that supplementing actually results in less sleep—not more.  

Night wakings continue to be common as breastfeeding infants mature. In a study of children who were breastfeeding at age two, night wakings were common throughout the second year of life. This pattern of night wakings is commonly observed in cultures where co-sleeping and full-term (aka, “extended”) breastfeeding are more usual (Elias, Nicolson, Bora, & Johnston, 1986).

Night wakings protect infants 

Night wakings have been reported as more common in infants who bedshare with a parent, yet the wakings and bedsharing (when done safely) may actually protect infants from sudden infant death syndrome (SIDS) (Mosko, Richard, & McKenna, 1997; Mosko, Richard, McKenna, & Drummond, 1996). The latest research hypothesises on the biological origins of sudden infant death syndrome (SIDS) and colic and conceptualises a neuro-physiological model of the human infant’s breathing system that tries to account for our species susceptibility to SIDS and inconsolable crying (McKenna, Middlemiss, Tarsha, 2016). The critical period for SIDS is up to eight months of age (with the peak at two to three months), and night wakings may serve as a protective mechanism. In fact, if we look at parenting historically and cross-culturally, frequent night wakings, coupled with co-sleeping and breastfeeding, are the norm against which we should be comparing other infant sleep behaviors.

My child was sleeping through the night and suddenly it’s stopped.

Imagine you’ve been waking regularly with night feeds and arousals, but as time passes they are decreasing. Then you realize you’re now sleeping in nice, long chunks. Hours of sleep all at once! And it’s wonderful. Then suddenly, as quickly as it came, it’s gone. Your wonderful, sleeping-through-the-night child is suddenly waking again. This experience, which is a reality for many, can cause frustration and despair accompanied by the feeling that you’ve done something wrong, or that you must do something to get uninterrupted sleep back again.

Here’s the thing: you didn’t do anything. A return to night waking after periods of sleeping through the night is entirely normal. Many children’s sleep will cycle like this for a while. In fact, researchers looking at sleep patterns have found that often between 6 and 12 months, infants who had previously been sleeping long stretches suddenly start to wake more frequently at night (Scher, 1991, 2001). In one long-term study, it was found that there was no stability in night wakings or even sleep duration between 3 and 42 months (Scher, Epstein, & Tirosh, 2004).

What causes the change in sleeping pattern? 

It’s likely to be a variety of reasons, unique to each child. For some, it may be a growth spurt, teething, or learning to crawl. For others, it may be a cognitive leap that has them buzzing more so than usual or the appearance of separation anxiety. We may never know the actual reason. But as children age, and each develops a circadian rhythm, they will go through cycles of sleep—some more convenient for parents than others. Be aware that these changes are entirely normal, even though they can be frustrating. Once you know that changes are to be expected, you may feel better prepared, or at least not so anxious when facing sleep disruptions once again.

My child wakes up at 2 a.m., and is up for one to two hours!

One mother remembers very clearly her daughter doing this. At around 14 months, she woke up in the middle of the night and didn’t seem ready or able to go back to sleep for a couple of hours, no matter what strategies her parents tried. This continued regularly for some months. And then, as quickly as it started, it stopped, and hasn’t happened again in over a year.

Nobody knows why—although researchers continue to explore the physiological underlyings of sleep—but we do know that such extended night wakings are common until around three years of age (Weinraub, Bender, Friedman, Susman, Knoke, Bradley, et al., 2012). Often the wakings are brief and the child settles quickly. Other times, settling takes longer. In either case, these wakings do not suggest your child has a sleep problem. Increased night wakings, call-outs, and crying are more common around six months of age or so, and again as infants near two years. These wakings may simply be one (of many) manifestations of separation anxiety, a normal experience as infants learn that they exist separately from their caregivers (Middlemiss, 2004).

Some argue that night wakings in toddlerhood reflect sleep problems, but several studies have found that night waking is relatively common between age 12 and 24 months (Richman, 1981; Goodlin-Jones, Burnham, Gaylor, & Anders 2001; Scher 2001; Weinraub et al., 2012).

A parent’s perceptions about what constitutes a sleep problem may be triggered by either a disconnect between expectations of uninterrupted sleep and a toddler sleep pattern that arguably falls within the range of normal, or by the impact that night waking has on the parent’s quality of sleep and daily functioning (Loutzenhiser,  Ahlquist, & Hoffman, 2012). However, although changes in sleep patterns may be inconvenient and frustrating, they are normal occurrences in the context of a healthy parent-child relationship.

Parents can experience greater stress and worry when they view night wakings as an indication of problems, rather than normal sleep patterns that will alter (Middlemiss, 2004). As we have learned from many parents, understanding these disruptions as normal can go a long way toward making them more bearable.

Understanding individual patterns in sleep

My child won’t go to sleep before 10 p.m.

It is not uncommon in some Western societies to assume that young children must be in bed by, for example, 7 p.m. to develop “good sleep habits.” Unfortunately, that’s just not realistic for many families. It’s not because parents are negligent about bedtimes. Some children simply have a different circadian rhythm, or in some families a later schedule works. Some children will continue this pattern into their toddler years and beyond.

Cross-cultural data on bedtimes for infants and toddlers show that later bedtimes are actually quite frequent in predominantly Asian countries (Mindell, Sadeh, Wiegand, How, & Goh, 2010).  Whereas the mean bedtime for children in predominantly Caucasian countries was found to be 8:42 p.m., it was a full hour later for predominantly Asian countries (with a mean at 9:44 p.m.), with the latest mean bedtime being 10:17 p.m. in Hong Kong. Notably, the rising time was also significantly later in these countries. A concurrent finding was that the vast majority of children in predominantly Asian countries sleep either in the parents’ bed or room. Owing to these sleeping arrangements, such children may naturally have a sleep schedule closer to that of their parents.

What is important to remember is that a late bedtime, in and of itself, is not a problem. If it poses a problem for the family, then parents may want to adjust the bedtime routine (Mindell, Telofski, Weigand, & Kurtz, 2009), or start the routine earlier in small increments in order to gradually move to an earlier bedtime (Richman, 1981). 

My child sleeps less than (or more than) the recommended amount, no matter what I do!

Sleep guidelines tell parents that newborns should sleep around 16 to 18 hours, that at two years of age, children require a total of 13 hours sleep, and so on. When researchers explore what are healthy recommendations, the answers are not at all clear, and are often based on how much children slept at different points in history (Matricciani, Olds, Blunden, Rigney, & Williams, 2012).

It is important to remember that these are only recommendations. Each child is different, and the recommendations may not fit every child. Some will require more sleep, and some less. Notable signs of true sleep deprivation include:

• rubbing eyes
• looking dazed
• not focusing on people or toys
• becoming overly active late at night
• having a hard time waking up in the morning. 

By paying attention to cues and behaviors, you will be able to tell if your child is getting enough sleep, regardless of the exact number of hours. Sleep is important, but does not have to be one long, uninterrupted stretch. Interestingly, researchers are now telling us that waking in the middle of the night is common in adulthood and was viewed as normal in past eras—the “first sleep” lasted about four hours, with an awake period in between, followed by a “second sleep” of another four hours. (A fascinating book on the history of nighttime is At Day’s Close: Night in Times Past by Roger Ekirch. Norton 2005).

Normal parent behaviors and why they won’t hurt your child

My child is still sleeping in our bed.

Many parents who sleep with their child get comments along the lines of, “Your child will never leave if you don’t move him” or “What about your sex life?” Parents end up questioning if they are doing the right thing, or if they will end up with a 16-year-old who still wants to crawl into bed with mom and dad every night. First, let’s address the question of when a child leaves your bed. Rest assured, your child will not be dragging you off to college so they can still sleep with you—even if you don’t force them out of the bed.

The age at which children are ready to move into their own room varies widely, and bedsharing is quite common worldwide. Notably, bedsharing rates in Scandinavian and Asian countries are much higher than those in the U.S. or Canada (Mindell, Sadeh, Wiegand, How, & Goh, 2010; Nelson & Taylor, 2001; Welles-Nystrom, 2005; for a review, see Cassels, 2013). Parents polled about the age at which their children initiated the move to another room report ages as young as 18 months, and as old as 10 years.

Some factors that influence the transition age include:

• having a sibling with whom to room-share
• the presence of a new baby in the bed, necessitating attention to safety
• disrupted sleep on arrival of a new baby
• the child’s own developmental needs

Each family needs to consider the factors that are relevant for their particular child. 

The research on extended bedsharing has not found any social, emotional, or cognitive detriment for bedsharing children relative to children who were placed in their own room in infancy (Abel, Park, Tipene-Leach, Finau, & Lennan, 2001; Barajas, Martin, Brooks-Gunn, & Hale, 2011; Keller & Goldberg, 2004; Okami, Weisner, & Olmstead, 2002).

The second issue that is often brought up is the marital relationship when there is a family bed. Research reports no influence on marital satisfaction when bedsharing is intentional (Messmer, Miller, & Yu, 2012). When bedsharing is in reaction to child sleep problems, parents may report greater stress on their relationship. As to intimacy, parents of co-sleepers and bedsharers often find creative ways to make sure their own needs are met. There are excellent (and humorous) blogs on the topic if you’re in need of some extra assistance.

Knockout drops

My child only goes to sleep breastfeeding.

Breastfeeding is what sends little ones to sleep quickly. Although many parents do not think twice about this when their infants are tiny, they start to worry about this behavior as the child grows. It doesn’t help that falling asleep while breastfeeding is listed as a sleep disorder by researchers (Meltzer & Mindell, 2006), or that family and friends will tell you that you’re harming your child, that she will never learn to fall asleep on her own. “Sleep experts” will recommend not letting your infant fall asleep on your breast for fear of creating this “bad habit” (Meltzer & Mindell, 2006), recommending instead that you rouse your little one before putting her down.

If you don’t have a problem with breastfeeding your child to sleep, you don’t need to worry about it for your child. A child who is tired enough will fall asleep with or without breastfeeding. Although falling asleep at the breast may remain a preference for the child (full of the closeness and intimacy that is so necessary for bonding), it will not be a necessary step. As children age, they will fall asleep in various places and positions. Young infants should not be forced to fall asleep without comfort; they may need to breastfeed to feel relaxed and safe. 

Remember that all children eventually wean. Breastfeeding and cuddling to sleep provide closeness and comfort associated with positive developmental outcomes. Children will seek this as a natural part of development. This is not a bad thing; it is simply offering the closeness that is a natural and healthy part of parenting for your child’s growth.

Breast milk in the evening contains more tryptophan (a sleep-inducing amino acid). Tryptophan is a precursor to serotonin, a vital hormone for brain function and development. In early life, tryptophan ingestion leads to more serotonin receptor development (Hibberd, Brooke, Carter, Haug, & Harzer, 1981).

Nighttime breast milk also has amino acids that promote serotonin synthesis (Delgado, 2006; Goldman, 1993; Lien, 2003). Serotonin makes the brain work better, keeps one in a good mood, and helps with sleep-wake cycles (Somer, 2009). So, because of tryptophan and its wider effects, it may be especially important for children to have evening or night breast milk for reasons beyond getting them to sleep.

The other concern that is brought up is that infants and children who fall asleep at the breast (or even in-arms) often wake looking for the same environment in which they fell asleep (Anders, Halpern, & Hua, 1992). This can lead to crying upon waking when they find themselves in a different environment, such as a crib. 

Parents who bedshare and breastfeed have reported decreased signaling as infants learn to seek mother’s breast and latch themselves on to breastfeed when waking at night. Though arousals continue to be greater in bedsharing dyads (Mosko, Richard, & McKenna, 1997), this natural interaction provides a soothing and simple way to care for infants. In these cases, when the children are developmentally ready, putting them down nearly asleep, and letting them finish the process on their own, may help reduce wakings that result in signaling for the parent. 

The mother is the baby’s environment

My child only naps when I’m outside/walking/on me.

Wouldn’t it be nice if children wanted to sleep exactly where we wanted to put them? It would be wonderful, but unfortunately, it’s not how most babies sleep. We’ve heard mothers complain about having to be outside walking for a nap to happen, while living in cities with blizzards and 30 below freezing, or only happening when mom is walking constantly (inside or out), so that naptimes provide no respite for mom and can be downright unpleasant.

Interestingly, the most common situations involve touch, sound, or movement—all abundant for the infant while still in the womb. In comparison to other mammals,  human babies are born much earlier because of head size (if they got any bigger, they could not get through the birth canal (Trevathan, 2011), so for at least nine months, their bodies expect an “external womb.”

So is it much of a surprise that outside the womb, babies expect the same things to lull them to sleep?  With respect to touch, we know that oxytocin plays a huge role in feelings of contentment, security, and love, all of which affect the quality of our sleep (Uvnäs-Moberg, 2003). It is not difficult to imagine that infants who are physically close to their caregivers, experiencing a release of oxytocin, are much more likely to fall asleep and remain asleep.

A second factor is sound—notably, the caregiver’s heartbeat, familiar from the womb. When the mother holds her infant, her heartbeat, voice, and breathing can offer a form of white noise that helps him feel safe and remain asleep, though the same may happen when another caregiver holds the infant as well. 

When there is no one to hold the child, the use of a white noise machine to block out some of the more abrasive sounds of our environment while still providing background noise can help with infant sleep. White noise machines have been successful in inducing infant sleep (Spencer, Moran, Lee, & Talbert, 1990), and at assisting some parents achieve better sleep (Lee & Gay, 2011).

The third factor, movement, was also abundant in the womb, when the baby was in a soft, liquid pouch being swayed regularly. Remember how your baby was awake in utero when you were resting? It’s because he was sleeping while you moved. Modern parents in Western cultures often focus on the car ride to get their infants to sleep. The lull of the car coupled with the snugness of the car seat can send infants into a drowsy state, allowing them to nap contently while their parents drive aimlessly around. 

Movement-induced sleep can work if mom or dad pushes the baby in a stroller, letting them run errands, or go for a walk or run. Possibly best of all, babywearing promotes movement, touch, and sound, all while allowing the caregiver generally to carry on. Babywearing may provide the best form of “external womb” for the baby’s optimal brain and body development (Narvaez et al., 2013).

The take-home point, though, is that it is normal for infants to prefer to sleep in contact with others rather than away from what many people would consider the “ideal” sleep space. Even though adults may prefer it, a bed in a quiet room is not necessarily ideal for infants. For  safe napping when wearing a baby, please click here.

What parents perceive to be problematic infant sleep patterns that require “fixing” are actually quite normal and developmentally appropriate. 

Let your child be your guide.

References

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Kathleen Kendall-Tackett‘s biography.