When will my baby settle into a sleep routine? Can I change my baby’s sleep time routine? How long can I expect my baby to sleep?

The short answers: At around about 10-12 weeks (2-3 months) babies begin to develop a body clock – a critical factor in a regular sleep routine. There are environmental and care factors that influence your baby’s sleep routine, such as feed times, light, and noise. Babies sleep for increasing periods of time at night but even by 6 months the longest unbroken sleep is on average 6 hours (but probably varies greatly baby to baby as discussed in the last post).

The long answers are based on an article by Davis, Parker, and Montgomery (2004). Davis and colleagues (2004) offer a lot of insight into “normal” baby sleep. Unfortunately, most references provided did not give the details of the population, method, or statistics. Therefore I can’t comment on how much babies might differ, how applicable this is to different groups of babies, or what exactly was measured. I hope to corroborate these findings with further research.

Sleep routine changes at a glimpse

What to Expect1 Month6 Months3 years5 years
Longest continuous sleep period2.5 to 4 hours6 hours
Sleep cycle length50-60 mins50-60 mins60 mins90 mins
Cycles per sleep period1-22 long night sleep periods divided by one night feed6-8
1st Sleep typeActiveNREM (Quiet)NREM (Quiet)
Sleep influencesFeedingCircadian Rhythm (body clock)


Insight 1: Your baby’s body clock doesn’t emerge until 10-12 weeks of age. Implications for establishing a sleep routine.

So what? So in the first 10-12 weeks:

  • You can’t expect predictable sleep and wake times
  • Attempts to create a regular sleep routine are likely to fail
  • Noise and light shouldn’t affect sleep “patterns” as much

From 10-12 weeks:

  • Regular bedtimes and feed times may begin to emerge
  • You can start trying to implement a routine that fits you and your baby

Details: The body clock, called circadian rhythm, is one of the processes that determines when you feel sleepy, when you wake up, and when you feel wide awake. The other process is the homeostatic process, which basically says that the longer it is since your previous sleep the more the need for sleep increases.

Insight 2: Body clocks are “set” by light and dark, milk and meals, temperature, noise, and many other environmental factors

So what? You can do a number of things to support the development of a body clock that fits both you and your baby.

  • Sleepy time is “set” by dark, quiet, low-activity conditions. Therefore incorporating these conditions into your regular bedtime routine should help to set bedtime (try to avoid bright artificial bright lights, TV, etc before bed).
  • Regular meals and regular daytime naps may help to regulate night-time sleep also.

Variation: Are body clocks genetic? How much can they be manipulated? I will look into these questions.

Details: Body clocks naturally run on about a 25-hour cycle unless synchronised by the elements above.

Insight 3: Even by 6 months of age, the longest usual sleep period is only 6 hours.

So what? You may not get a straight 8 hours sleep for 6 months or more. Do what you can to prepare yourself, your family, and your work situation to make broken sleep manageable or share the load.

Variation: I couldn’t access the original source of this data. However Iglowstein (2003) provides some insight. Iglowstein (2003) examined the duration of night and daytime sleep via surveys completed by the mothers. Night sleeps were calculated from bedtime to morning wake time and therefore may include multiple night-wakings.

Night time sleep duration figure
Figure 1: Night-time sleep duration falls between red lines for 96%, between blue lines for 80%, and between green lines for 50% of babies from birth to 9 months. Data from Iglowstein 2003.


Figure 1: Night-time sleep duration falls between red lines for 96%, between blue lines for 80%, and between green lines for 50% of children from 1 to 16 years of age. Data from Iglowstein 2003.

Figure 2: Night-time sleep duration falls between red lines for 96%, between blue lines for 80%, and between green lines for 50% of children from 1 to 16 years of age. Data from Iglowstein 2003.

Upshots from the graphs in Figures 1 and 2 are:

  • Even if 6 month olds sleep only 6 hours at a time. Average total night-time sleep is 11 hours.
  • Variation is huge initially and gets smaller. 80% of 1 month olds sleep 6-12 hours at night, 6 month olds 9.5-12.5, 1 year olds 10.5-13 hours. The other 20% fall outside those ranges.
  • Night-time sleep increases in the first year of life to somewhere between 9.5 and 13.5 by 1 year of age (for the vast majority of babies).
  • From about 1.5 or 2 years of age there is a steady decline in night-time sleep down to 6.6-9.5 hours for most 16 year olds.

Night-time sleep duration increases initially but this is mainly a re-allocation of sleep hours. Total sleep duration decreases from birth for most babies.

Details: According to Davis et al (2004) the longest continuous sleep period in newborns is usually 2.5 to 4 hours and in 6 month olds is 6 hours.

Insight 4: Infants and young children wake often at night. They usually fall back asleep unless something has changed.

Caution: It was not clear at what ages children do this. Recommendations may not apply to particularly young babies.

So what? Try to avoid putting your child in bed already asleep. Leave the room before your child falls asleep (less important if you share a room). Don’t rush in if you hear your child stirring, playing, or even briefly crying out, wait a moment to see if they resettle.

Details: Night-wakings often occur 5-7 times a night and last about 1-5 minutes each. During these wakings children often open their eyes and survey their surroundings. If there have been significant changes, they may wake fully. For more information see the following podcast show notes:


Insight 5: Sleep occurs in relatively regular cycles of 50-60 minutes in the first 3 years extending to 90 minutes by age 5

So what? Sleep cycles affect when babies, infants, and children are most easily woken and when they will naturally wake. Given that frequent night wakings are likely for the first 3 to 5 years, helping children to learn to feel safe and comfortable in their cot or bed is a worthwhile investment.

Details: Babies and children can move from one sleep cycle to the next without waking, but commonly wake briefly at around 11pm, 2am, 3am, and 6am after an 8pm bedtime.

Newborns tend to start with “active” sleep and progress to “quiet” sleep. During active sleep babies suck, twitch, smile, frown, move their arms and legs, and breath irregularly. Quiet sleep, as per the name, involves little movement and rhythmic breathing. Active sleep becomes REM (rapid eye movement) sleep and quiet sleep becomes NREM (non rapid eye movement) sleep in older infants. I will continue to use the more intuitive names “active” and “quiet” sleep. From about 3 months the order begins to reverse, and by 6 months babies start with quiet sleep and progress to active sleep.

Insight 6: Active (REM) sleep is accompanied by paralysis but only from 6 months

So what? This may explain why babies under 6 months or so can wake themselves up with flailing arms and feet if not wrapped and why this becomes less of a problem as they get older. It may also explain those dreams where you feel like you’re running but not going anywhere.

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Davis, K. F., Parker, K. P., & Montgomery, G. L. (2004). Sleep in infants and young children: Part one: Normal sleep. Journal of Pediatric Health Care, 18(2), 65-71.

Iglowstein, I., Jenni, O. G., Molinari, L., & Largo, R. H. (2003). Sleep duration from infancy to adolescence: Reference values and generational trends. Pediatrics, 111(2), 302.