Quick Answer: Most infants begin sleeping a stretch of 6 or more hours by around 6 months of age. About 70 to 80 percent of babies sleep through the night by 9 months. However, there is wide variation. Some babies manage long stretches from 2 to 3 months; others continue night waking past 12 months, which is still within the normal range. Always consult your paediatrician if you have concerns.
In This Guide
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What 'Sleeping Through the Night' Actually Means
The phrase "sleeping through the night" means something different for an infant than it does for an adult. For a 2-month-old, sleeping through the night often means a 4 to 5 hour stretch. For a 6-month-old, it usually means 6 hours or more. The adult definition of 7 to 9 uninterrupted hours is typically not realistic until well into the second half of the first year, and for many babies, later still.
Understanding this distinction saves a lot of parental anxiety. A baby who sleeps a solid 5-hour block at 10 weeks is, by clinical standards, sleeping through the night -- even though those same parents might feel they are still waking every few hours.
It is also worth knowing that all humans, infants and adults, wake briefly between sleep cycles. Adults generally go back to sleep without fully waking up. Infants have to learn this skill, which is essentially what sleep training supports. A baby who "sleeps through the night" is not sleeping without any arousals -- they are arousing and returning to sleep without needing parental intervention.
Sleep Milestones by Age
| Age | Total Sleep/Day | Night Sleep | Night Feeds | What to Expect |
|---|---|---|---|---|
| 0 to 1 month | 14 to 17 hours | No predictable stretch | Every 2 to 3 hours | Sleep and wake driven by hunger, no day/night distinction yet |
| 1 to 3 months | 14 to 17 hours | 3 to 5 hour stretches | 2 to 3 times | Circadian rhythm begins to develop; some longer night stretches emerge |
| 3 to 6 months | 12 to 15 hours | 5 to 6+ hours (variable) | 1 to 2 times | Sleep consolidating; some babies begin sleeping through; 4-month regression common |
| 6 to 9 months | 12 to 14 hours | 6 to 9 hours for most | 0 to 1 time | Majority sleeping through; good age for sleep training if not yet achieved |
| 9 to 12 months | 12 to 14 hours | 8 to 10 hours for many | Usually 0 | 70 to 80% sleeping through; 8 to 10 month regression may disrupt gains |
| 12 months and over | 11 to 14 hours | 9 to 11 hours | 0 | Consolidating to one daytime nap; most sleep through the night |
Why Infants Wake at Night: The Biology
Newborns have not yet developed a circadian rhythm. The suprachiasmatic nucleus, the brain's internal clock, is present at birth but not yet entrained to a 24-hour light-dark cycle. Melatonin production begins around 2 to 3 months, which is when the first hints of day-night organisation emerge. Until the circadian system matures, waking is driven by hunger and comfort, not a biological awareness of night versus day. This is not something that can be hurried -- it is a developmental process. Exposure to natural light during the day and darkness at night helps the circadian rhythm entrain faster.
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Why There Is So Much Variation
Why does one 4-month-old sleep 8 hours while another wakes every 2? Several factors explain the variation:
- Neurological maturity: Some babies' arousal systems mature earlier than others. This is partially genetic and not something parents can control.
- Feeding method: Breastfed babies typically wake more often than formula-fed babies, because breast milk is digested more quickly and the caloric density varies. This is not a problem with breastfeeding -- it is normal biology.
- Birth weight and gestational age: Premature or lower birth weight babies have smaller stomach capacity and higher caloric needs, which means more frequent feeds and later sleep consolidation.
- Sleep associations: Babies who learn to fall asleep in a specific way (nursed, rocked, held) will wake fully when that association is absent between sleep cycles. Babies who fall asleep independently can return to sleep more easily.
- Temperament: Some babies are simply more easily aroused or more sensitive to discomfort. This is a real factor, not parental failure.
What Helps Babies Sleep Longer
Evidence-Based Ways to Support Longer Sleep Stretches
- Consistent bedtime routine: A predictable 20 to 30 minute wind-down sequence (bath, feed, song, sleep) signals the brain that sleep is coming. Even young infants begin to respond to routine by 6 to 8 weeks.
- Drowsy but awake: Place the baby in the crib drowsy but not fully asleep as early as 6 to 8 weeks. This teaches the baby to associate the crib with the transition into sleep, rather than requiring full sleep onset before placement.
- Consistent sleep location: Babies who sleep in the same place consistently develop stronger sleep associations with that space.
- Room temperature: Keep the bedroom between 18 and 20 degrees Celsius. Overheating is both a SIDS risk factor and a common cause of night waking.
- Dark bedroom: Blackout curtains support melatonin production and prevent early morning light from triggering early waking.
- White noise: Consistent low-level white noise masks household sounds that might disrupt light sleep stages. Volume should not exceed 50 dB at the infant's ear level.
- Adequate daytime feeding: A baby who is taking enough calories during the day has less biological drive to feed at night. Discuss feeding adequacy with your paediatrician or public health nurse.
- Sleep training after 4 months: If the baby is healthy and developmentally ready, sleep training methods can help the baby learn to self-soothe between sleep cycles, which is the core skill behind sleeping through the night.
Sleep Regressions
Sleep regressions are periods when a baby who was sleeping well suddenly starts waking frequently again. They are developmentally driven and generally correspond to significant brain growth periods. The most common occur at:
- 4 months: Sleep architecture reorganises to be more adult-like, creating more frequent brief wake windows between cycles. This is often the most difficult regression.
- 8 to 10 months: Coincides with major cognitive and motor leaps (pulling to stand, separation anxiety development).
- 12 months: Often coincides with the transition from two naps to one, which temporarily disrupts night sleep.
- 18 months: Developmental leaps in language and autonomy can affect sleep.
The typical advice is to stay consistent with the approach that was working rather than reintroducing sleep associations during a regression. Most regressions last 2 to 6 weeks. Illness, teething, or major life changes (moving house, starting daycare) can also disrupt sleep independently of developmental regressions.
Sleep Exhaustion Is Real -- You Are Not Alone
In over 37 years of fitting Brantford families with mattresses, we have had many conversations with new parents who are simply exhausted. Sleep deprivation in the first year of a child's life is well documented as one of the most significant stressors for parents, and the impact on parental sleep quality is real. If you are a new parent struggling to get rest, your own sleep surface matters too. A supportive mattress that does not transfer your partner's movement, a good pillow, and a dark, quiet room help you take advantage of whatever windows of sleep you get. That is the angle we can genuinely help with.
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Call 519-770-0001Frequently Asked Questions
When do most infants sleep through the night?
Most infants begin sleeping for a stretch of 6 hours or more by 6 months of age. About 70 to 80 percent of babies are sleeping through the night by 9 months. However, there is significant variation. Some babies sleep 5 to 6 hour stretches as early as 2 to 3 months; others continue waking at 9 or 12 months, which is still within the normal range.
What does 'sleeping through the night' mean for infants?
For infants, sleeping through the night typically means a continuous stretch of 5 to 6 hours, not necessarily 8 or 9 hours as adults might define it. A 3-month-old who sleeps 5 hours without waking is, clinically, sleeping through the night. The expectation of an uninterrupted 8-hour night is usually not realistic until after 6 to 9 months.
Is it normal for a 6-month-old to still wake at night?
Yes, it is within the normal range. Studies have found that 38% of 6-month-olds were not sleeping through the night. While 6 months is often described as when sleep consolidation becomes possible, a significant proportion of healthy babies continue to wake at this age. If there are concerns about your baby's sleep or development, discuss them with your paediatrician.
Does the crib mattress affect how well a baby sleeps?
A crib mattress cannot make a baby sleep through the night, as this is primarily a developmental milestone. However, an appropriate firm, flat crib mattress ensures the baby is safe and supported during sleep. A mattress that does not fit the crib correctly or does not meet Health Canada standards may contribute to an uncomfortable or unsafe sleep environment.
Sources
- Mindell, J.A., et al. (2010). Developmental aspects of sleep hygiene: Findings from the 2004 National Sleep Foundation Sleep in America Poll. Sleep Medicine, 11(9), 765-770. doi.org/10.1016/j.sleep.2010.02.008
- Pennestri, M.H., et al. (2020). Uninterrupted infant sleep, development, and maternal mood. Pediatrics, 142(6), e20174330. doi.org/10.1542/peds.2017-4330
- Touchette, E., et al. (2005). Factors associated with fragmented sleep at night across early childhood. Archives of Pediatrics & Adolescent Medicine, 159(3), 242-249. doi.org/10.1001/archpedi.159.3.242
- Henderson, J.M.T., et al. (2010). Sleeping through the night: The consolidation of self-regulated sleep across the first year of life. Pediatrics, 126(5), e1081-e1087. doi.org/10.1542/peds.2010-0976
- Akacem, L.D., et al. (2015). The timing of the circadian clock and sleep differ between neonates and school-age children. PLOS ONE, 10(12), e0145120. doi.org/10.1371/journal.pone.0145120
Shop This Topic at Mattress Miracle
Popular picks at Mattress Miracle:
- Restonic ComfortCare Dalton & Albany pocketed-coil mattress
- Whitney flippable mattress
- Somnia 3.0 pillow
Or browse the mattress collection in our Brantford showroom.
Related Reading
- Sleep Training Baby: Methods and When to Start
- Crib Death (SIDS): Safe Sleep Guidelines for Parents
- Infant Pacifier: Benefits, Risks, and When to Stop
- Crib Mattress Size: Dimensions and What to Know
- When Do Infants Sleep Through the Night? Age, Timeline, and What Helps
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