What is normal sleep for a baby? Durham University’s Infancy and Sleep Centre explains

It is important to remember that sleep is a developmental process, and that sleep needs will change throughout our lifetimes.

Newborn babies may sleep for 18 or so hours a day, but often for only for two to three hours at a time. During the first year, overall sleep duration falls to around 15 hours, and the majority of sleep becomes concentrated during night-time as the circadian rhythms develop.

Circadian rhythms are biological processes which are roughly tied to the 24-hour day, and periods of daylight and dark. Processes regulated by our circadian rhythms include heart rate, temperature and our ‘body clock’, along with the production of hormones which make us feel sleepy or alert.

A review into 'normal' infant sleep duration showed...

A recent systematic review (Galland et al. 2012. Normal sleep patterns in infants and children: A systematic review of observational studies) drew together data from 34 studies relating to normal infant sleep duration. The chart below shows part of this data for babies aged up to one year. Data from each study and age range are represented by a dot which shows the average total sleep experienced. The dotted line shows the amount of variation around that average. It is clear that younger babies sleep longer overall, but there is also a lot of variation among individual babies, and within studies, for this group.

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Night-waking is normal during early infancy and healthy babies experience several awakenings per night at the end of sleep cycles.

Newborn babies have very small stomachs and need to feed often, so they wake at least every two to three hours to do so, sometimes more often. As babies grow, they are able to last slightly longer between feeds, however, human milk (and today’s infant formula containing chemically modified cows’ milk proteins) is quickly digested, and babies commonly need to feed frequently throughout the day and night-time.

Sleep in their first year

By the time babies are three months old, some (but not all) begin to start settling (sleeping through a night-time feed for a stretch of up to five hours). By the time they are five months old, half of them may have started to sleep for an eight-hour stretch on some nights. Generally, though, babies do not sleep all night, every night until they are close to a year old. One study investigating infant sleep duration found that 27% of babies had not regularly slept from 10pm to 6am by the age of one year. 13% of babies had not regularly slept through for five hours or more by the age of one year.

Sleeping Through the Night: The Consolidation of Self-regulated Sleep Across the First Year of Life. Henderson et al, 2010.

The myth about 'sleeping through the night!'

Popular beliefs about when babies should be ‘sleeping through the night’ are based on studies conducted in the 1950s and 1960s on groups of formula-fed babies. However, it is normal for babies – especially breastfed babies – to wake and feed at night throughout at least the first year.

Encouraging babies to ‘sleep through’ before they are ready to do so makes it difficult to keep on breastfeeding, and may encourage babies to develop mature sleep patterns out of sequence with their other circadian patterns, such as those controlling the regulation of temperature, hormone production and the genes that control our biological rhythms.

References:

Galland, B. C., Taylor, B. J., Elder, D. E., & Herbison, P. (2012). Normal sleep patterns in infants and children: a systematic review of observational studies. Sleep medicine reviews, 16(3), 213–222. https://doi.org/10.1016/j.smrv.2011.06.001

Henderson, J. M., France, K. G., Owens, J. L., & Blampied, N. M. (2010). Sleeping through the night: the consolidation of self-regulated sleep across the first year of life. Pediatrics, 126(5), e1081–e1087. https://doi.org/10.1542/peds.2010-0976