How to Get Your Newborn to Sleep Through the Night

Newborns cannot sleep through the night, and no technique or product will change that. Their brains lack a functioning circadian rhythm, their stomachs are too small to hold enough food for more than a couple of hours, and their sleep cycles are roughly half the length of an adult’s. The honest answer to this question is that you are working against biology in the first weeks, and the goal should shift from “sleeping through the night” to building the conditions that help your baby consolidate sleep as their brain matures. That process unfolds over months, not days, and understanding what is actually happening beneath the surface can make the wait more bearable and your interventions more effective.

Why Newborns Wake So Often

A newborn’s sleep cycle lasts roughly 47 minutes at term, compared to about 90 minutes in an adult.¹ Each cycle contains a large proportion of active (REM-like) sleep, and the transitions between cycles are shallow. Babies tend to partially wake at the end of each cycle. Adults do this too, but most of us roll over and fall back asleep without remembering it. Newborns haven’t learned to do that yet, so each transition is an opportunity for a full awakening.

On top of that, a term newborn’s stomach holds about 20 milliliters, which empties in roughly an hour when fed breast milk.² Stomach capacity grows over the first weeks and months, but in the earliest period, hunger returns rapidly. Expecting a baby to go five or six hours without eating when their fuel tank is the size of a cherry is asking the impossible. Frequent nighttime feeds are not a failure of sleep training; they are a physiological requirement.

When Longer Sleep Stretches Begin

The master clock in the brain does not start producing a reliable day-night signal right away. One longitudinal study found that a measurable circadian wake rhythm appeared around day 45 of life, coinciding with the time when melatonin levels began rising at sunset.³ Separately, research tracking melatonin metabolites in urine found little evidence of a rhythmic pattern before nine to twelve weeks in full-term infants.⁴ So the internal chemistry that tells the brain “it’s nighttime, stay asleep” simply doesn’t exist in the first month or two. Expecting a newborn to distinguish night from day is like expecting them to read a clock that hasn’t been built yet.

Premature babies may take even longer. The same melatonin research showed that neural centers responsible for rhythm generation do not accelerate their development just because a baby is born earlier. Corrected age, not birth date, is the better predictor of when longer sleep stretches emerge.

What “Sleeping Through the Night” Actually Means

The phrase itself is misleading. An influential early definition set the bar at sleeping from midnight to 5:00 a.m., which is only five hours. A later study examined three definitions: midnight to 5:00 a.m., any unbroken eight-hour stretch, and a family-friendly 10:00 p.m. to 6:00 a.m. block. Half of infants met the first two criteria by three months, but the more practical 10-to-6 standard wasn’t reached by half of babies until around five months.⁵ A review of this body of research noted that most infants can sleep eight continuous hours by six months, and nine or more hours after that.⁶

Even those milestones overstate how reliable the achievement is. A study using nightly diaries over two weeks found that among infants whose mothers reported they “slept through the night,” the babies actually managed six consecutive hours on only about five of thirteen nights. Roughly one in five babies never hit that mark during the tracking period, while a slim 7 percent did it every single night.⁷ The takeaway: sleeping through the night is not a switch that flips on. It’s a probabilistic skill that comes and goes for months before it stabilizes.

What You Can Actually Do in the Early Weeks

You can’t force a newborn’s circadian clock to mature faster, but you can give it the right inputs. Light exposure is the most powerful signal. A scoping review found that more daytime light exposure was associated with better daytime wakefulness and longer nighttime sleep in infants.⁸ Conversely, exposure to bright light at night can delay or disrupt the developing rhythm.⁹ In practical terms, this means getting your baby into natural daylight during the day (even indirect light near a window counts) and keeping nighttime feeds and diaper changes dim and boring. Avoid turning on overhead lights during night wakings. A dim red or amber nightlight is enough to see what you’re doing without sending a daytime signal to the baby’s brain.

If you’re breastfeeding, the milk itself contains circadian signals. Breast milk produced at night has higher concentrations of melatonin and tryptophan, while daytime milk is richer in cortisol and activity-promoting amino acids.¹⁰ These fluctuations are measurable and consistent.¹¹ For parents who pump and store milk, this raises an interesting question about whether feeding daytime-expressed milk at night might blunt these cues. The research hasn’t definitively shown that matching pumped milk to time of day improves infant sleep, but the biological plausibility is strong enough that some researchers have argued for labeling stored milk by time of expression.¹²

Swaddling, White Noise, and Their Limits

Swaddling can help some newborns settle by reducing the startle reflex that jerks them awake. It promotes longer stretches of quiet sleep and reduces the frequency of sleep-stage transitions.¹³ But this comes with a safety trade-off: those same properties that keep a baby asleep also suppress the arousability that protects against SIDS. Infants who were not routinely swaddled showed increased arousal thresholds and decreased cortical arousals when swaddled during quiet sleep at three months, meaning it was harder to wake them up.¹⁴ Swaddling must stop before the baby can roll over, typically around two to four months. A baby who rolls face-down while swaddled is in a dangerous situation.

White noise machines are popular, and they can mask household sounds that startle a sleeping baby. The concern is volume. Testing of fourteen infant-marketed devices found that nine of them exceeded 85 decibels at the maximum setting when placed 10 centimeters from a microphone, which is close to where many parents position them near the crib. No device exceeded that threshold at 30 centimeters or beyond.¹⁵ A scoping review warned that continuous moderate-intensity white noise may have negative effects on auditory development based on animal models, though low-intensity exposure appeared potentially beneficial.¹⁶ The practical advice: keep the machine across the room (not inside or on the crib), run it at the lowest volume that still masks background noise, and consider using a timer so it isn’t running all night.

Safe Sleep Comes Before Sleep Optimization

Any discussion of infant sleep strategies has to acknowledge the non-negotiables. The American Academy of Pediatrics recommends placing babies on their backs on a firm, flat surface with no loose bedding, pillows, or soft objects. The prone (stomach-down) position carries an odds ratio for SIDS ranging from about 2 to 13, depending on the study, and infants placed on their side who roll to their stomach face an even higher risk.¹⁷ Inclined sleepers, dock-a-tots, and memory foam surfaces are specifically discouraged because they can create pockets that restrict breathing if the baby shifts position.

Bed-sharing is a contentious topic. For babies under three months, even when parents don’t smoke and the baby is breastfed with no other risk factors, bed-sharing roughly tripled the risk compared to room-sharing in a crib, though the absolute numbers remained small.¹⁸ Parental smoking dramatically increases the danger: unadjusted odds for bed-sharing SIDS were nearly 14 times higher when the mother smoked, compared to about twice the risk for non-smokers.¹⁹ The safest arrangement is the baby sleeping in a separate sleep surface in the same room as a caregiver.

Pacifiers are worth mentioning here. Infants who used pacifiers were found to arouse from sleep at lower auditory thresholds than non-users, meaning they woke up more easily in response to external stimuli.²⁰ While that sounds counterproductive if you’re trying to maximize sleep, easier arousal is thought to be protective against SIDS. The AAP recommends offering a pacifier at nap time and bedtime after breastfeeding is established.

Sleep Training Is for Older Babies, Not Newborns

Formal sleep training methods are not appropriate for newborns. Most pediatric sleep experts recommend waiting until at least four to six months, when the circadian rhythm is more established and the baby can physiologically go longer between feeds. But for parents reading about this topic in anticipation or desperation, the evidence on these methods is worth knowing.

A large review of controlled studies found that behavioral interventions produced lasting improvements, with over 80 percent of treated children showing meaningful change that held for three to six months.²¹ A randomized controlled trial comparing graduated extinction (going in at increasing intervals) and bedtime fading (temporarily pushing bedtime later to build sleep pressure) found that both methods improved sleep compared to controls, with no adverse effects on parent-child attachment or child behavior at follow-up.²²

The cortisol question nags at many parents. A small study found that by the third night of an extinction-based program, infants had stopped crying at bedtime but still showed elevated cortisol levels, while their mothers’ cortisol had dropped because the crying cue was gone.²³ This is the study most often cited by critics of cry-it-out methods. However, the larger randomized trial mentioned above, which measured salivary cortisol across both intervention groups, found small-to-moderate cortisol declines in the sleep-training groups compared to controls, not increases.²² The disconnect likely reflects differences in study design and sample size; the cortisol-elevation finding came from a very small group over just three days, while the reassuring data come from a larger, longer trial.

Does Feeding Method Change the Timeline?

The relationship between breastfeeding and infant sleep is not what many people expect. A large study tracking sleep trajectories found that fully breastfed infants had longer total night-sleep durations at multiple time points than formula-fed infants. But those same breastfed babies also woke more often between six and twelve months.²⁴ Another study found that exclusively breastfed infants at three months had a shorter longest sleep period at night than formula-fed infants at both three and six months.²⁵

So breastfed babies may sleep more total hours but in shorter stretches, while formula-fed babies may consolidate sleep into longer blocks sooner. The popular advice to “top up with formula to help baby sleep longer” has a grain of truth in the consolidation data, but the total-sleep-duration picture actually favors breastfeeding. For parents already breastfeeding, switching to formula solely for sleep gains is trading one metric for another, and the difference narrows as babies get older.

When Reflux or Other Medical Issues Are the Problem

Some babies wake frequently for reasons beyond normal development. Gastroesophageal reflux is one of the most common culprits. Research using sleep monitoring found that the onset of a reflux episode was significantly associated with a change in sleep stage, regardless of whether the reflux was acidic or non-acidic.²⁶ A separate study confirmed that reflux was a frequent cause of sleep interruption and that non-acidic reflux was just as disruptive as the acidic kind.²⁷ If your baby arches their back during feeds, spits up frequently, or seems uncomfortable lying flat, mention it to your pediatrician. No amount of sleep hygiene will override untreated reflux.

Cow’s milk protein allergy, ear infections, and eczema are other conditions that can fragment sleep. If your baby’s sleep suddenly worsens after a period of improvement, a medical cause is worth investigating before assuming it’s behavioral.

The Cost of Infant Sleep Disruption for Parents

The effects on parents are real and measurable. Mothers who reported being woken three or more times per night, or who got fewer than six hours of total sleep, were significantly more likely to score above the clinical threshold for major depressive symptoms.²⁸ The rate of clinically significant depression was roughly double among mothers of chronically waking infants compared to mothers whose babies slept through.²⁹ This is not about feeling tired. Fragmented sleep in the postpartum period is a genuine risk factor for clinical depression, and treating it as something mothers should just push through is unhelpful.

Sharing the nighttime load helps. A study examining paternal involvement in nighttime care found that when fathers were more involved, both mothers and fathers reported fewer nocturnal awakenings, with the association being strongest for infants aged eight to twelve months.³⁰ Whether this reflects direct soothing by a second caregiver or simply the effect of another adult intercepting wakings before they escalate isn’t clear, but the practical implication is straightforward: tag-teaming nighttime duties benefits the whole household.

Night Waking and Attachment

A common fear is that letting a baby cry or not responding instantly will harm the parent-child bond. The data here is more complex than either side of the debate usually acknowledges. One longitudinal study found that more frequent and longer nighttime awakenings at three months were actually associated with higher attachment security with fathers at 24 months, but lower attachment security with mothers.³¹ A separate study found that securely attached infants decreased their night wakings over time, while insecure-resistant infants continued waking into the second year.³²

These findings suggest that the relationship between sleep and attachment runs both ways. Secure attachment may help a baby learn to self-settle, and babies who wake more may elicit different caregiving responses from mothers versus fathers. What the research does not support is the simple narrative that responding to every cry creates better attachment or that sleep training damages it. The largest randomized trial of behavioral sleep interventions found no differences in attachment or child behavior between intervention and control groups.

How Cultural Expectations Shape What Feels Normal

Whether infant night waking is considered a “problem” depends heavily on where you live. A cross-cultural comparison spanning predominantly Asian and predominantly Caucasian countries found enormous variation. Bedtimes ranged from 7:27 p.m. in New Zealand to 10:17 p.m. in Hong Kong, and total sleep time ranged from about 11.6 hours in Japan to 13.3 hours in New Zealand. Bed-sharing ranged from under 6 percent in New Zealand to over 83 percent in Vietnam. Perhaps most revealing, the percentage of parents who perceived their child had a sleep problem ranged from 11 percent in Thailand to 76 percent in China.³³

These gaps aren’t explained by the babies being biologically different. They’re explained by different cultural expectations about where babies should sleep, when they should sleep, and whether waking at night is a problem to solve or a normal phase to ride out. If you are feeling like a failure because your two-month-old wakes every two hours, it is worth knowing that in most of the world and most of human history, that was simply what babies did, and nobody framed it as something that needed fixing.