Infant sleep problems:
An evidence-based guide
© 2017 Gwen Dewar, Ph.D., all rights reserved
Struggling with infant sleep problems? Baby sleep is
different than adult sleep. A lot of the stuff that drives us crazy is
developmentally normal behavior.
For example, newborns need to feed frequently (8-12 times
every 24 hours), and the transition to longer, consolidated bouts of sleep is
In general, we shouldn't expect babies to sleep for more than 4-5
hours at a stretch until they are at least 3 months old.
But that doesn't mean we can't improve things. On the
contrary, there's a lot we can do.
Might your baby's sleep troubles be caused by
a medical condition? That's possible, so you might want to review these common
infant medical problems that interfere with sleep.
But in this article we'll focus on
other culprits -- the everyday stumbling blocks on the path to easier, more restful
nights. Here is a list of ten things that might be going wrong, and what you
can do about them.
1. Your baby's internal clock is out of sync with the 24-hour day
First things first: Does your baby appreciate that nighttime
is for sleeping? If not, you're fighting an uphill battle. Most infants don't
develop strong, hormonally-driven circadian rhythms until they are 12 weeks
old, and some babies take considerably longer (Jenni and Carskadon 2005; Jenni
et al 2006).
You might assume that this is one of those developmental things we
just have to wait out. But that's not quite true. The evidence suggests we have
help young babies attune themselves faster. If we lay the right groundwork early on, we may avoid some infant sleep problems later on.
So support your baby's tendency to awaken at roughly the same
time each morning, and expose him or her to daylight during the morning and
afternoon. In addition, include your baby in everyday activities. The hustle and bustle of social life helps set your baby's inner clock.
And avoid exposure to artificial lights before and during bedtime --
particularly LED lights and other light sources that feature light from the
blue part of the spectrum. Experiments show that blue light is particularly
effective at blocking the brain's production of melatonin, a hormone that
promotes sleepiness. A little exposure to blue light can delay sleepiness for
an hour or more.
more tips, see "How to help baby adapt to the 24-hour day" in my article
about newborn sleep.
2. Your baby is hungry
If your baby is very young, there may be little you can do
about the timing of feedings. Newborns need to feed frequently. However, if you
feed your baby shortly before your own bedtime, you might give yourself more
uninterrupted sleep time, and encourage your baby to sleep longer at night
(Pinilla and Birch 1993).
The evidence comes from an experimental study of 26 breastfed
newborns. Half the parents were instructed to offer babies a big meal between
10pm and midnight. They were also told to avoid feeding babies immediately after they
woke up during the night. For instance, instead of feeding first, a parent
might change the baby's diapers. In addition, parents were instructed to expose
their babies to strong cues about the natural, 24 hour day.
The intervention appeared to be very successful. Eight weeks
after training began, 13 out of 13 infants in the treatment group were sleeping
quietly from midnight to 5am (Pinilla and Birch 1993). Only 3 out of 13 control
infants were doing so.
It sounds promising, but keep in mind: This is a small study that needs replication. Moreover, the study design doesn't permit us to
tell which of the interventions were important, and we don’t know if the effect
was long-lasting. It's also unclear if going 5 hours without feeding is in the
best interest of every 8-week old infant.
But as long as your baby is getting
enough food and fluids -- and your pediatrician approves -- these tactics are
worth trying. For more information about nursing young babies, see this article
about feeding infants on cue.
3. Your baby is getting too much excitement (and maybe too much screen time) in the hours leading up to bedtime
Some infant sleep problems are caused by adults who make life a little too exciting before bedtime. Rambunctious play? Animated verbal interactions? These can rev up your baby's sympathetic nervous system—the system
in charge of keeping him or her alert. So researchers recommend that parents make the last 2-3 hours
before bedtime quiet and calm (e.g., Glaze 2004).
But exciting interpersonal activities aren't the only sources of trouble. In a recent survey of
715 British parents, researchers found that babies who spent time playing with
touch screens (on phones and other devices) took longer to fall asleep at night. They also had shorter nocturnal
sleep times. Every additional hour that a baby used touch screens was
associated with about 26 minutes less sleep during the night (Cheung et al 2017).
researchers didn't collect information about when babies used touch screens, and can't say for sure if touch
screen use contributes to infant sleep problems. But the blue light emitted by
tablets and other electronic devices is known to delay drowsiness. So it's
plausible that this blue light, and the stimulating nature of media content, are to blame.
4. You are too quick to intervene when you think your baby is awake
This is crucial to know: Babies sometimes make noises--and
may even cry out--when they are still asleep or only partially aroused. Babies are "sleep talkers."
Furthermore, video studies of sleeping infants reveal that
babies as young as 5 weeks can spontaneously resettle themselves after waking up
in the middle of the night (St. James Roberts et al 2015). Sometimes the babies
in this study went back to sleep quietly. In other cases, the infants cried or
fussed briefly (for about one minute) before going back to sleep on their own
(St. James Roberts et al 2015). Either way, these babies fell back to sleep on
their own, without coaching or marked distress. That's the sort of thing you
want to promote.
So intervening too soon can backfire. You think you are being
proactive, responding quickly so your baby will be able to go back to sleep
quickly. But instead you are awakening a sleeping baby, or interfering with a
drowsy baby who was about to nod off. Ouch. To avoid becoming the cause of infant sleep problems, don't jump in at the first signs of movement
5. Your attempts to soothe your baby are too stimulating
This is the flip side of being too interesting before bedtime: Parents can also cause infant sleep problems by creating too much excitement after a baby has awakened during the night. Babies are social creatures, and are easily stimulated by talk
and other forms of communication. So if you want your baby to go back to sleep
quickly, avoid engaging him or her in conversation or play. As you tend to
your baby's nighttime needs, keep things comforting, but dull and quiet. And
don't forget to avoid those artificial lights. Keep things as dark as
6. You aren't consistent in your approach
It's easy to get off-track when you are frustrated or tired.
Sometimes you might use overly-stimulating soothing techniques. Other times --
when it seems that nothing works -- you might withdraw from your baby altogether
(France and Blampied 1999). It's human nature, but it's confusing for the baby,
and it can make infant sleep problems worse.
To help avoid this scenario, take the time to create a
single, consistent approach to your infant sleep problems. Research the science of infant sleep patterns, and
decide what approach is best for you and your baby. Thinking things through
ahead of time will help you stick to the plan, and may have additional
psychological benefits for you. Parenting studies suggest that getting informed
can boost your sense of competence and confidence, and protect you from
feelings of frustration and despair (Heerman et al 2017).
7. Your baby's bedtime is too early -- or too late
When should babies go to bed? It can be hard to figure out.
Some parents overestimate infant sleep requirements, or try to force bedtime on
an infant that isn't sleepy. That's bad for a couple of reasons. In the
short-term, the baby resists bedtime, and everyone is unhappy. In the
long-term, your child is learning to associate bedtime with the failure to fall
asleep. It could be a recipe for developing bedtime resistance and insomnia
(LeBourgeois et al 2013).
Other parents might be fooled by babies that seem active and
energetic. If they won't settle down, isn't that proof that they don't need to
sleep yet? Possibly, but they could also be hyper-reactive -- strung out or
"overtired." Their stress response systems may be stuck on
"high," overriding the physiological responses that would ordinarily
allow them to become drowsy.
What to do? If you're uncertain, review these signs of
infant tiredness, and read about range of sleep times observed in normal,
healthy babies. If you suspect your baby's bedtime is too early, try the gentle
infant sleep training programs described below. If overtiredness is the
problem, pick an earlier bedtime, and help your baby wind down by introducing
some soothing, low-key bedtime rituals. For more tips, see this article about
solving bedtime problems.
8. Irregular timing -- or a lack of routines -- is making it harder for your baby to settle down
You've heard the advice that children should go to bed at
the same time each night. You've also heard that it's important to observe a
bedtime routine, a habitual sequence of activities that comfort children and
wind them down for bed.
Are these things really necessary to avoid infant sleep
problems? Evidently not, because in many parts of the world bedtimes are fluid
or irregular, and babies go to bed without
fanfare (e.g., Morelli et al 1992; Ottaviano et al 1996). Indeed, it's
the norm among hunter-gatherer societies -- the peoples whose life-ways most
closely resemble those of our ancestors. And hunter-gatherers are remarkable for their
lack of sleep complaints (Yetish et al 2015; Samson et al 2017). It appears you
can lead a healthy life without observing regular bedtimes or reading bedtime
But we should keep a couple of things in mind.
First, while hunter-gathers tend to vary their bedtimes over
the course of a week, they are very consistent about when they wake up in the
morning (Yetish et al 2015). This is important, because waking up at roughly
the same time each day helps keep the body's circadian rhythms attuned.
Second, people in these societies can make up for a shortened
night's sleep by napping (Worthman and Melby 2002; Samson et al 2017).
So if your baby's irregular bedtimes are leading to
irregular mornings -- waking up at different times each day --
this could cause
infant sleep problems (see #1). And if your baby isn't getting the
chance to catch up on lost sleep, irregular bedtimes could cause
behavior problems (Kelly et al 2013).
What about bedtime routines? If they aren't necessary, are
they at least helpful? Experimental studies suggest they can be. Parents have
improved infant sleep problems by leading babies through the same sequence of
calming activities each night (Mindell et al 2009). And a large international survey
has reported links between bedtime routines and nighttime behavior: According
to parents, babies who experienced consistent routines fell asleep faster. They
also spent less time awake in the middle of the night (Mindell et al 2015).
9. Your baby is napping too late in the afternoon
Sleep pressure (the physiological urge to sleep) builds up
the longer we've been awake. So it shouldn't surprise us if a baby -- having awakened
from a long nap only a couple of hours earlier -- has trouble falling asleep at
bedtime. If this seems to be the trouble, try extending the last waking period
of your baby's day.
That may seem hard to do if you've got a drowsy baby at
5pm; but remember, you don't have to arrive at the perfect schedule all at once.
You can work towards the goal in steps, trying to make the last nap of the day
end at an increasingly earlier time over the course of a week or so. When
parents have managed to lengthen waking time before bedtime, their babies have
required less help settling down and experienced fewer infant sleep problems (Skuladottir et al 2005).
10. Your baby doesn't know how to self-soothe
Sleep science has proven the point: Everybody wakes up
during the night, and we do it quite frequently, even if we don't remember
these wakings the next day.
So eliminating night wakings isn't a realistic goal. Rather,
we should focus on making night wakings less
disruptive. As mentioned above, research shows that babies sometimes
resettle themselves without becoming stressed or waking up other people. What
can we do to promote this behavior?
One crucial tactic, noted in #4, is to stop undermining
these spontaneous acts of re-settling. Don't jump in prematurely. Your baby
might actually be asleep, or on the verge of falling back to sleep on his or
her own. By intervening too soon, you can create infant sleep problems.
But can we go further? In some Western countries parents are advised to
avoid soothing their babies to sleep. For instance, Richard Ferber argues that
parental soothing trains babies to associate sleep with parental intervention
(Ferber 2006). As a result, children don't develop their own, self-soothing
abilities. When babies wake up during the night (and all babies do), they cry
until their parents come to their aid.
The remedy, according to this argument is to follow certain
rules. Don't let the baby fall asleep in
your arms. Instead, at bedtime, put your baby to bed before he or she has
What does the research tell us? When babies fall asleep at
the breast--or are put to bed after they have fallen asleep--babies are less
likely to soothe themselves back to sleep when they awaken again during the
night (e.g., Anders 1979; Anders et al 1992; Ferber 1986; Goodlin-Jones et al
2001). In addition, researchers have found that parents who feed, hold, or rock
their babies to sleep tend to report more night wakings (Anuntaseree et al
2008; Mindell et al 2010).
That sounds like evidence in support of reduced parental
soothing at bedtime. But there's an obvious complication:
Babies often cry or protest when caregivers withdraw.
It's a natural
behavior. Throughout human history, babies have stayed in close proximity to
their caregivers. Being left alone meant something was wrong. A baby was at
risk for neglect, abandonment, or predation (Hrdy 1999).
So it's little wonder
that our ancestors evolved emotional and behavioral responses to separation --
responses that would help ensure that babies stayed close (Panksepp 1998).
What, then, should we do when babies cry?
Ferber has proposed his own solution, which is to leave the
baby alone for increasingly lengthy intervals, ignoring cries, until the infant
learns to give up (Ferber 2006).
It's not intended for very young babies.
Researchers warn that such sleep training should not be attempted until infants are at
least 6 months old (Owens et al 1999; France and Blampied 1999). Moreover, the American
Academy of Pediatrics recommends that parents share a bedroom with their babies
for at least six months after birth because it may lower the risk of SIDS and "facilitate…comfort
and monitoring of the infant" (Moon et al 2016).
But when it comes to making nighttime less disruptive, this
method -- called "graduated extinction" -- has a successful track
record. Babies become less likely to cry in the middle of the night when they
awaken. Parents report fewer infant sleep problems.
This can be a relief to desperate parents. But
many people reject the approach. It's stressful to implement, and critics worry
about the possible effects of enforcing its central features -- (1) babies left
alone, unable to perceive the immediate presence of caregivers, and (2) parents
acting as if they are insensitive to the baby's distress.
Major media headlines
to the contrary, studies haven't yet supplied us with strong evidence about
Unresolved questions about "cry it out" tactics
One highly-publicized study tested the
long-term effects of sleep training on more than 170 babies, but did so by lumping together several
different training strategies, including a program that didn't involve leaving infants alone (Price et al 2012).
Thus, we can't know if families who used
graduated extinction experienced different outcomes than families who used
other methods -- like those that kept babies and parents together in the same
In addition, this study failed to determine if parents in the control
group attempted sleep training. This, too, is crucial, because it means we
can't draw conclusions about a failure to detect differences between groups.
Maybe outcomes were similar because treatments were similar: Babies in both
groups were exposed to a mixed bag of sleep training techniques.
A more recent study presents similar interpretative
problems (Grandisar et al 2016). The researchers took the helpful step of distinguishing between graduated extinction and other types of sleep training. But they didn't measure what parents assigned to
the control condition did with their babies. Nor did they keep track of where
babies slept with respect to their parents -- alone or in a shared room.
Moreover, this was a much smaller study, and one marked by substantial amounts of missing data, as well as some discrepancies in the published numbers. For example, at one time point during the study, almost half the families failed to participate. Researchers filled in the missing data with their own estimates (Grandisar, personal communication).
And it's interesting to reflect on results that the popular press
largely ignored. The researchers tested for attachment security at the
end of the study, and found that only 7 out of 13 (54%) of "graduated
extinction" babies were scored as
securely attached to their parents. By contrast, babies in the control
group fared a bit better: 5 out of 8 babies (62%) were scored as
We can't draw any conclusions from this difference.
The sample sizes are too small, and six families chose not to
participate in this final test, which may have biased the results. For
instance, what if having a securely-attached baby made parents more
inclined to participate? Or less inclined? But it underscores the
difficulty in making inferences from small studies with missing data.
So as I write this in May 2017, we're still a long way from
settling questions about the effects of graduated extinction, especially
for parents concerned about leaving babies alone and unable to perceive
presence of caregivers. And that's important because there are other approaches
of sleep training that don't involve leaving babies alone, and these approaches
have similarly successful track records.
Furthermore, scientific surveys indicate that babies don't
have to sleep in their own rooms to develop quieter sleep habits. In places
like Hong Kong, babies and children often share a room with others. In many cases, they share a bed with a
parent. But researchers have found no links between sleep location and night
wakings (Yu et al 2017). It appears to be the use of active soothing measures
-- like feeding or rocking a baby to sleep -- that is linked with trouble. Not necessarily
So if you want to encourage your baby to self-soothe, it's
worth taking a look at these sleep training alternatives to graduated
extinction. And keep in mind the work of Douglas Teti, who has found that one
of the most important predictors of infant sleep problems is whether or not parents
are emotionally available at bedtime -- responding with sensitivity to a baby's
needs, and projecting a calm, reassuring mood (Teti et al 2010). Regardless of
whatever else you might do, and whatever sleep arrangements you adopt,
maintaining emotional availability at bedtime can help your baby settle down.
Putting it all together: A checklist for coping with infant sleep problems
- Establish regular day-time cues. Make sure your baby is
exposed to natural daylight and daytime activity. Include baby in the daily
hustle and bustle.
- Establish regular night-time cues. As bedtime approaches,
shift down from stimulating activities to more passive, sleepy, sedate
activities. Dim the lights. And consider introducing special bedtime rituals, like
reading bedtime stories or singing lullabies.
- Tank up before bedtime. As noted above, babies may sleep for
longer stretches at night if you feed them shortly before bedtime.
- Keep your nighttime interactions calm and low-key. Be responsive, but boring. Avoid making noise, avoid moving your baby around, and avoid eye contact. Some infant sleep problems are caused by parents making too much of a fuss.
- Watch out for intervening too quickly when you think your baby has awakened. You might end up awakening a sleeping baby, or preventing your baby from falling back to sleep spontaneously.
If your baby is over 6 months old, consider these gentle sleep training programs. Because they
don’t require babies to fall asleep alone, they minimize distress for both
parents and infants.
If you're worried about a possible medical problem, or
something just doesn't seem right, talk to your doctor. Most infant sleep
problems aren't caused by medical conditions, but some are. Read more about it
References: Infant sleep problems
Adams LA and Rickert VI. 1989. Reducing bedtime tantrums:
Comparison between positive bedtime routines and graduated extinction.
Pediatrics 84(5): 756-761.
Anders TF. 1979. Night waking in infants during the first
year of life. Pediatrics 63: 860-864.
Anders TF, Halpern LF, and Hua J. 1992. Sleeping through the
night: A developmental perspective. Pediatrics 90(4): 554-560.
Anuntaseree W, Mo-suwan L, Vasiknanonte P, Kuasirikul S,
Ma-a-lee A, Choprapawan C. 2008. Night waking in Thai infants at 3 months of
age: association between parental practices and infant sleep. doi:
10.1007/s12519-017-0025-6. [Epub ahead of print]
Cheung CH, Bedford R, Saez De Urabain IR, Karmiloff-Smith A,
Smith TJ. 2017. Daily touchscreen use in infants and toddlers is associated
with reduced sleep and delayed sleep onset. Sci Rep. 13;7:46104.
Fauroux B. 2007. What's new in paediatric sleep? Paediatr
Respir Rev. 8(1):85-9.
Eckerberg B. 2004. Treatment of sleep problems in families
with young children: effects of treatment on family well-being. Acta Paediatr.
Ferber R. 1986. Sleepless child. In: C. Guilleminault (ed),
Sleep and its disorders in children. New York: Raven Press, pp. 1410163.
Ferber R. 2006. Solving your child’s sleep problems: New,
revised, and expanded edition. New York: Fireside.
Ferber SG, Laudon M, Kuint J, Weller A, Zisapel N. 2002.
Massage therapy by mothers enhances the adjustment of circadian rhythms to the
nocturnal period in full-term infants. J Dev Behav Pediatr. 23(6):410-5
France KG. 1992. Behavior characteristics and security in
sleep disturbed infants treated with extinction. J Pediat Psychol 17: 467-475.
France KG and Blampied NM. 1999. Infant sleep disturbance:
Description of a problem behaviour process. Sleep Medicine Reviews 3(4):
Glaze DG. 2004. Childhood insomnia: Why Chris can’t sleep.
Pediatric Clin N Amer 51: 33-50.
Goodlin-Jones BL, Burnham MM, Gaylor EE, and Anders TF. 2001.
Night-waking, sleep organization, and self-soothing in the first year of life.
J Dev Behav Pediatrics 224(6): 226-233.
Grandisar M, Jackson K, Spurrier NJ, Gibson J, Whitham J, Sved Williams A, Dolby R, Kennaway DJ. 2016. Behavioral Interventions for Infant Sleep Problems: A Randomized Controlled Trial. Pediatrics 137(6).
Heerman WJ, Taylor JL, Wallston KA, Barkin SL. 2017.
Parenting Self-Efficacy, Parent Depression, and Healthy Childhood Behaviors in
a Low-Income Minority Population: A Cross-Sectional Analysis. Matern Child
Health J. 2017 Jan 13. doi: 10.1007/s10995-016-2214-7. [Epub ahead of print]
SB. 1999. Mother nature: Maternal instincts and how they shape the
human species. New York: Pantheon Books.
Jenni OG and Carskadon MA. 2005. Normal human sleep at
different ages: Infants to adolescents. In: SRS Basics of Sleep Guide.
Westchester, Illinois: Sleep Research Society, pp. 11-19.
Jenni OG, DeBoer T, and Acherman P. 2006. Development of the
24h rest-activity pattern in human infants. Infant behavior and development 29:
LeBourgeois M, Wright, Jr., KP, LeBourgeois OP, Jenni OG.
2013. Dissonance Between Parent-Selected Bedtimes and Young Children's
Circadian Physiology Influences Nighttime Settling Difficulties. Mind, Brain,
and Education 7(4): 234-242.
Levesque BM, Pollack P, Griffin BE and Nielsen HC. 2000.
Pulse oximetry: What’s normal in the newborn nursery? Pediatric pulmonology
Luddington-Hoe SM, Cong X, and Hashemi F. 2002. Infant
crying: nature, physiologic consequences, and select interventions. Neonatal
Network 21(2): 29-36.
McKenna JJ and McDade T. 2005. Why babies should never sleep
alone: A review of the co-sleeping controversy in relation to SIDS, bedsharing
and breast feeding. Paediatric Respiratory Reviews (2005) 6, 134–152.
Mindell JA, Kuhn B, Lewin DS, Meltzer LJ, Sadeh A and the
American Academy of Sleep Medicine. 2006. Behavioral treatment of bedtime
problems and night wakings in infants and young children. Sleep 29: 1263-1281.
Mindell JA, Li AM, Sadeh A, Kwon R, Goh DY. 2015. Bedtime
routines for young children: a dose-dependent association with sleep outcomes.
Mindell JA, Telofski LS, Wiegand B, Kurtz ES. 2009. A
nightly bedtime routine: impact on sleep in young children and maternal mood.
Mitchell EA, Thompson JMD. 2003. Snoring in the first year
of life. Acta Paediatrica, 92(4), 425-429.
Panksepp J. 1998. Affective Neuroscience: The
Foundations of Human and Animal Emotions. New York: Oxford University Press.
Pinilla T and Birch LL. 1993. Help me make it through the
night: behavioral entrainment of breast-fed infants' sleep patterns.
Philbrook LE, Hozella AC, Kim BR, Jian N, Shimizu M, Teti
DM. 2014. Maternal emotional availability at bedtime and infant cortisol at 1
and 3 months. Early Hum Dev. 90(10):595-605.
Price AMH, Wake M, Epi GD, Ukoumunne OC, Hiscock H, Epi GD.
2012. Five-Year Follow-up of Harms and Benefits of Behavioral Infant Sleep
Intervention: Randomized Trial. Pediatrics. 130(4):643-51.
Owens JL, France KG, and Wiggs L. 1999. Behavioural and
cognitive-behavioural interventions for sleep disorders in infants and
children: A review. Sleep Medicine Reviews 3(4): 281-302.
Pantley E. 2002. The no-cry sleep solution: Gentle ways to
help your baby sleep through the night. New York: McGraw-Hill.
Reid MJ, Walter AB, and O’Leary SG. Treatment of young
children’s bedtime refusal and nighttime wakings: A comparison of
“standard" and graduated ignoring procedures. Journal of Abnormal Child
Psychology 27: 5-16.
Sadeh A. 1994. Assessment of intervention for infant night
waking: Parental reports and activity-based home monitoring. J Consult Clin
Samson DR, Crittenden AN, Mabulla IA, Mabulla AZ, Nunn CL.
2017. Hadza sleep biology: Evidence for flexible sleep-wake patterns in
hunter-gatherers. Am J Phys Anthropol. 162(3):573-582.
Sears W and Sears M. 1996. The fussy baby book: Parenting
your high-need child from birth to age five. New York: Little, Brown and
Skuladottir A, Thome M, and Ramel A. 2005. Improving day and
night sleep problems in infants by changing day time sleep rhythm: A single
group before and after study. Int J Nurs Stud. 42(8): 843-850.
Teti DM, Kim BR, Mayer G, Countermine M. 2010. Maternal
emotional availability at bedtime predicts infant sleep quality. J Fam Psychol.
Worthman CM and Melby M. 2002. Toward a comparative
developmental ecology of human sleep. In: Adolescent Sleep Patterns:
Biological, Social, and Psychological Influences, M.A. Carskadon, ed. New York:
Cambridge University Press, pp. 69-117.
Yetish G, Kaplan H, Gurven M, Wood B, Pontzer H, Manger PR,
Wilson C, McGregor R, Siegel JM.2015. Natural sleep and its seasonal variations
in three pre-industrial societies. Curr Biol. 25(21):2862-8.
Yu XT, Sadeh A, Lam HS, Mindell JA, Li AM. 2017. Parental
behaviors and sleep/wake patterns of infants and toddlers in Hong Kong, China.
World J Pediatr. 2017 Mar 22. (epub ahead of print)
this text are derived from an earlier (2008) Parenting Science
article with the same title, "Infant sleep problems: an evidence-based guide."
Image credits for infant sleep problems
The following images are protected by this creative commons license, and should be attributed to the creators listed:
Image of sunset by fdecomite / flickr
Image of baby with tablet by Humbolthead / flickr
Image of baby staring at viewer by Jim Champion / flickr
Image of baby gazing out window by Nana B. Agyel / flickr
Image of baby sleeping in the sunlight by shawn / flickr
Montage of baby-wearing - historical images and Hadza photograph by Idobi
Father soothing infant by Andres Nieto Porras / wikimedia