Newborn sleep patterns: A survival guide for the science-minded parent

© 2008 Gwen Dewar, Ph.D., all rights reserved

As every parent knows, the world of newborn sleep is exotic and strange. Newborns sleep at odd times. They seem oblivious to differences between night and day. And they awaken frequently.

Put these sleep characteristics together in one small, mewling bundle...and you get some very, very tired parents.

But understanding the science of newborn sleep can help you cope. In this article, I review

• fundamental differences between newborn and adult sleep patterns

• circadian rhythms, and how you can help your baby develop them

• sleep cycles in the newborn, and their implications for putting babies to bed

• tips for preventing newborns from waking up, and

• advice for improving your own sleep

Throughout, I focus on babies under four weeks of age. For information about older infants, see my article on baby sleep patterns.

If you are looking for information about newborn sleep safety, see these science-based tips for reducing the risk of SIDS.

Newborn sleep patterns: Are there any?

To the sleepless parent, newborn sleep might seem totally disorganized.

Newborns sleep in short bouts—typically ranging from 30 minutes to 4 hours—at seemingly random times throughout the day and night.

To make things worse for you, newborns awaken easily. This is because they spend a large portion of their sleep time in “active sleep,” a light sleep state characterized by fluttering eyelids; relatively rapid, irregular breathing; occasional body movements; and vocalizations (grunts or brief cries).

Finally, newborns vary greatly in the total amount of time they spend sleeping. In the first few days, the average newborn sleeps between 16-18 hours a day (Iglowstein et al 2002). By four weeks, newborn sleep averages about 14 hours. But the range is considerable. Some four week old babies sleep as little as 9 out of 24 hours. Others sleep for 19 hours a day (Iglowstein et al 2002).

These individual differences can be disconcerting, especially if your baby sleeps less than average. It’s tough enough to live with the “average” newborn. When newborn sleep time is shorter than average, parents may feel especially stressed. Not only do parents get less sleep themselves, they may worry that there is something wrong with their baby—-or with their parenting.

Newborn sleep rhythms: Why newborns seem to sleep—and wake—around the clock

The timing of adult sleep is governed by circadian rhythms—-physiological changes that follow a 24-hour cycle. Many of these changes are influenced by your exposure to light.

When you expose yourself to sunlight each morning, you help maintain your internal clock. Even if you are sleep-deprived, morning light exposure helps ensure that you will be more alert during the day than you are at night. As the day wears on and darkness falls, your body begins to produce less cortisol (a hormone that keeps you alert) and more melatonin (the hormone of drowsiness). When you expose yourself to bright artificial lights at night, you interfere with these changes and may find it harder to fall asleep (Dement and Vaughan 1999).

Unfortunately for sleepless parents, newborn sleep is not governed by circadian rhythms.

It doesn’t start that way. During pregnancy, fetuses are tuned into their mothers’ physiological cues about day and night. Fetal heart and respiratory rates speed up when Mom is active and slow down when she is sleeping (Mirmiran et al 2003). Such changes may be influenced by maternal hormones, particularly melatonin. Maternal melatonin passes through the placenta and may direct the fetus’ internal clock (Torres-Farfan et al 2006).

But after birth, this intimate hormonal connection is broken, and newborns must rely on their own internal clocks. But they haven’t yet developed their own circadian rhythms of melatonin production (Kennaway 1996). Nor have newborns developed circadian rhythms for the production of cortisol.

Instead, the life of the newborn revolves around a new problem: Getting fed. Newborn sleep patterns are shaped by the length of time it takes them to feed, digest, and become hungry again.

For most newborns, this means feeding every 2-3 hours (or less). Sleep episodes are brief and spaced in fairly regular intervals around the clock.

Nevertheless, newborn sleep isn’t completely divorced from the natural rhythms of the 24-hour day. Studies show that circadian rhythms begin developing in the first days after birth. For example, a German study reported that 2-day-old babies were more wakeful and slept for shorter periods during the daytime (Freudigman and Thoman 1998).

Another German study showed that during the second week postpartum, babies slept more at night than they did during the day (Korte 2004). And, in Japan, Matsuoka and colleagues (1991) reported that 1-week old infants slept more often after feedings that occurred between midnight and 4am than after feedings at any other time of day. By the second week, infants slept more frequently between midnight and 8 am than they slept at other times (Matsuoka et al 1991). This was true even though infants continued to receive night time feedings.

This doesn’t mean that your newborn’s sleep schedule will resemble yours any time soon. It takes about 12 weeks for infants to show day-night rhythms in the production of melatonin, the “sleep hormone” (Rivkees 2003). And circadian changes in cortisol—a hormone that regulates waking—may take even longer to emerge (Rivkees 2003).

Overall, babies may take 3-5 months before they “settle” at night—meaning that they sleep for more than 5 hours at a stretch (Jenni et al 2006; Pinilla and Birch 1993).

But scientific evidence suggests that even newborns are receptive to environmental cues about time. And you can take advantage of this fact to help shape newborn sleep patterns.

How to help baby adapt to the 24-hour day

• Make baby a part of your daily routine. Researchers argue that social cues may have the greatest influence on newborn sleep patterns (Custodio et al 2007; Lorh et al 1999). When mothers include their newborns in their daily activities, newborn sleep patterns adapt more rapidly to the 24-hour day. One study took continuous measurements of mother-infant activity patterns for four months after birth. Newborns who were active at the same time of day as their mothers quickly adapted to the daily schedule (Wulff and Siegmund 2002).

• Reduce stimulation at night. When baby wakes for night time feedings, keep activity to a minimum. Make as little noise as possible, and avoid moving your baby around. Ideally, you want to avoid waking her “all the way up.” But if that’s not possible, at least try to minimize the hustle and bustle.

• Expose your newborn to natural lighting patterns. Light cues may not influence newborn sleep patterns as much as social cues do. But they are still important. In a study of preterm infants kept in hospital wards, babies exposed to natural lighting patterns—brighter during the dark, darker during the night—adapted to the 24-hour cycle more quickly than those exposed to constant, low levels of light (Rivkees et al 2004). In another study of full-term infants, babies who were exposed to more afternoon light slept better at night (Harrison 2004).

• Try infant massage. One study reports that newborns who received 14 days of massage therapy (beginning when they were about 10 days old) showed more mature sleep patterns in later weeks. At 12 weeks, the massaged infants had higher levels of nocturnal melatonin (Ferber 2002).

• Breastfeed if you can. Breast milk contains tryptophan, an amino acid that is used by the body to manufacture melatonin. Tryptophan levels rise and fall according to maternal circadian rhythms, and when infants consume tryptophan before bedtime, they fall asleep faster (Steinberg et al 1992). It’s therefore possible that breastfeeding helps newborn sleep patterns synchronize with the 24-hour day (Cubero et al 2005). This hypothesis was tested by feeding infants formula fortified with varying concentrations of tryptophan. When infants were given low levels of tryptophan during the day and high concentrations at night (mimicking the natural fluctuations of breast milk), infants fell asleep faster at night and got more sleep overall (Cubero et al 2007).

• Stick close to baby when she falls asleep. There isn’t yet enough research to prove the point, but it’s possible that sleeping close to your baby may help her develop circadian rhythms. A study of preterm infants reports changes in infant body temperature were synchronized with peaked when babies were co-sleeping with parents (Thomas and Burr 2002)

Newborn sleep cycles: Why newborns are light sleepers

When adults fall asleep, we pass through a series of sleep stages, including bouts of deep (“slow wave”) sleep, and, finally, REM (rapid eye movement) sleep. REM is famous for its association with dreaming. But it’s also known for its distinctive pattern of brain activity, which resembles that of the busy, waking brain. Adults are much more likely to awaken during REM than they are during deep sleep.

At the end of a REM session, the sleep cycle is completed. Adults either wake up, or begin another sleep cycle. A single sleep cycle lasts about 90-100 minutes.

Newborn sleep follows a different pattern. When a newborn first falls asleep, she enters into immediately into “active sleep.” This rather restless sleep state is the newborn-equivalent of REM (rapid eye movement) sleep in adults. Just as adults are more likely to awaken during REM, newborns are more likely to awaken during active sleep (Anders 1979; McNamara et al 2002).

Newborns remain in active sleep for about 25 minutes, after which they slip into a deeper sleep state known as “quiet sleep.” Compared to active sleep, quiet sleep is characterized by slower, more rhythmic breathing, little movement, and no eyelid fluttering. Babies are less likely to awaken during quiet sleep, but this situation doesn’t last long. After another 25 minutes or so, the sleep cycle ends. Newborns then either awaken or begin another 25 minute stretch of active sleep (Anders 1979; McNamara et al 2002).

So newborn sleep is different in several important ways. For one thing, newborns spend much more time in active sleep than adults spend in REM. Whereas adults spend only 20% of their sleep time in REM, newborns spend 50% of their sleep time in active sleep. As a result, newborns spend a much greater proportion of the time “sleeping light.”

For another thing, newborn sleep cycles are much shorter than are adult sleep cycles. Instead of 90-100 minutes, the average newborn sleep cycles lasts only 50 minutes or so. As a result, newborns are vulnerable to awakening much more frequently.

This sounds like a raw deal for parents. But the truth is that newborns probably benefit from being light sleepers. Having a low threshold of arousal may protect babies from SIDS. And active sleep may be crucial for a newborn’s brain development (Heraghty et al 2008; Seigel 2005).

Of course, this doesn't mean that we should encourage our babies to spend more time in active sleep (and less time in quiet sleep) than is natural for them!

Quiet sleep is important, too. And while in active sleep, babies may experience more heart rate irregularities and more episodes of sleep apnea, conditions which may put babies at higher risk for SIDS. There is also evidence that SIDS cases have special problems arousing from active sleep (Kato et al 2003).

But the important point is that the typical baby sleep pattern--arousing frequently from sleep--is probably beneficial to babies.

How to keep your light sleeper from waking all the way up

• If your newborn falls asleep in your arms, don’t attempt to put him down until he has achieved the quiet state of newborn sleep. Remember that babies begin each sleep cycle in active sleep, during which time they may flutter their eyelids, breathe irregularly, and twitch. Babies remain in active sleep for about 25 minutes, and if you try to move them during this period they are likely to awaken.

• Try safe swaddling. Swaddling--the practice of wrapping a baby in a cloth or blanket to restrict her movement—-may improve newborn sleep. A recent experiment tested whether swaddling improved the sleep of babies aged 6-16 weeks. When babies were swaddled and placed on their backs, they slept longer and were less likely to awaken spontaneously. However, during REM sleep, swaddled infants were MORE likely to wake up in response to noise (Franco et al 2005). So if you try swaddling, keep things quiet. And be sure to follow swaddling safety guidelines. DNever place a swaddled baby on his stomach—this increases the risk of SIDS. Keep baby cool, too, because swaddled babies can get overheated. Also, don’t swaddle too tightly. When babies are swaddled to tightly around the hips and knees, they are at risk for developing hip dysplasia. When babies are swaddled too tightly around the chest, they are at greater risk for respiratory infections. To avoid these risks, don’t constrict your baby’s chest and swaddle your baby loosely around the lower body, so she can move her hips and knees freely (van Sleuwen et al 2007). The aim of swaddling is to reduce the baby’s ability to flail her arms around. So you don’t need to wrap her tightly like a mummy—just enough to keep her arms close to her body.

• Increase your newborn’s dietary DHA. DHA is a fatty acid found in fish oil and other dietary sources. It’s important for brain development, and may play a role in shaping sleep patterns as well. In one study, children who consumed low levels of DHA had reduced amount of slow-wave (deep) sleep (Faglioli et al 1989). In another study, pregnant women with higher blood levels of DHA gave birth to babies who spent more time in quiet sleep (Cheruku et al 2002). DHA is found in breast milk, so it’s seems plausible that boosting your DHA intake could improve your breastfed newborn’s sleep patterns. If you bottle-feed, find a baby formula that contains DHA.

• Tank up the baby before you go to sleep. Whether you breastfeed or bottlefed, try to give the baby an especially large meal before your own bedtime. This will encourage your baby to sleep longer.

• Check out my article on baby sleep aids, which includes more tips for improving newborn sleep.

Staying sane: How to improve your own sleep

Newborn sleep patterns take their toll on parents. In a study tracking the sleep patterns of mothers from pregnancy through the postpartum period, maternal sleep worsened after childbirth and continued to deteriorate until about 12 weeks postpartum (Kang et al 2002)—-the time when newborn sleep patterns begin to show marked circadian rhythms (Nishihara et al 2000).

Twelve weeks isn’t forever, but it can seem like it when you are severely sleep restricted. As you struggle to cope with newborn sleep patterns, don’t forget to look after yourself. Here are some tips to help you get more sleep—-and better survive the newborn period:

• Sleep when the baby sleeps. This is hardly original advice, but it’s very good advice. Naps will help you catch up on your sleep. And—-if you are too tired to sleep—-simply resting with your baby will help you repair. Keep in mind, too, that people can fall asleep without realizing it. In numerous lab studies, subjects who awaken from the first stage of sleep often deny that they were asleep at all (Dement and Vaughan 1999). Even if it seems you are just “lying there,” you might be getting a little cat nap!

• Breastfeed if you can. Parents may get more sleep when their babies are breastfed. A recent study reports that the parents of breastfed babies averaged 40-45 minutes more sleep time than did the parents of formula-fed babies (Doan et al 2007).

• If you are breastfeeding, you are likely to get more sleep if you keep baby nearby. A recent study found that breastfeeding women got more sleep when they co-slept with baby (Quillin and Glenn 2004). In fact, mothers who co-slept and breastfed got more sleep than did mothers who bottle-fed their babies (Quillin and Glenn 2004).

• If your baby is asleep, don’t worry about changing diapers. If your baby can’t sleep because she needs a diaper change, she’ll let you know. And a little urine is unlikely to awaken her anyway. In a recent experiment, researchers injected water into the diapers of sleeping infants to see if this would wake them up (Zotter et al 2007). It didn’t.

• Get sunlight and avoid artificial lighting at night. Make sure you expose yourself and your baby to bright light during the day. And keep lights out—-or at least dimmed—-after sunset. As noted above, natural lighting helps influence newborn sleep patterns. But it also helps you keep your own circadian rhythms from drifting, which is important if you are going avoid insomnia and be a source of day-time cues for your newborn.

• Let a friend or family member watch baby while you take a nap…even if this means your breastfed baby will take some of his meals from a bottle. Lactation experts often discourage breastfeeding moms from bottle feeding babies for the first 3-4 weeks. The worry is that supplemental feeds will lead to a decreased milk supply and endanger successful breastfeeding in the long-term. But you need to balance this against the negative effects of severe sleep restriction. Lack of sleep puts mothers at increased risk of illness and postpartum depression. And—-besides making you miserable—-postpartum depression has a variety of negative effects on your baby. If you are at the end of your rope, you need to get help.

• Trust your instincts. If something feels wrong with you or the baby, talk to your physician.

• Remember that things will get better. Newborns have special sleep patterns and special needs. But things will start to get better around 12 weeks postpartum.

References: What scientific studies say about newborn sleep

Anders TF. 1979. Night-waking in infants during the first year of life. Pediatrics 63: 860-864.

Cheruku SR, Montgomery-Downs HE, Farkas SL, Thoman EB, and Lammi-Keefe CJ. 2002. Higher maternal plasma docosahexaenoic acid during pregnancy is associated with more mature neonatal sleep-state patterning. Am J Clin Nutr 76:608-13.

Cubero J, Valero V, Sánchez J, Rivero M, Parvez H, Rodríguez AB, Barriga C. 2005. The circadian rhythm of tryptophan in breast milk affects the rhythms of 6-sulfatoxymelatonin and sleep in newborn. Neuro Endocrinol Lett. 26(6):657-61.

Cubero J, Narciso D, Terrón P, Rial R, Esteban S, Rivero M, Parvez H, Rodríguez AB, Barriga C. 2007. Chrononutrition applied to formula milks to consolidate infants' sleep/wake cycle. Neuro Endocrinol Lett. 28(4):360-6.

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Faglioli I, Barconcini P, Ricour C, and Salzarulo P. 1998. Decrease of slow-wave sleep in children with prolonged absence of essential lipids intake. Sleep 12: 495-499.

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Content last modified 5/08

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