When Do Newborns Sleep Longer At Night?

Average timeline of an infant's sleep cycle

A child's sleeping pattern changes as they grow up, as their needs change and as their body and mind develop. It's important to know and understand that not all babies will have a similar sleep schedule and each baby will develop at slightly different paces. Below you will find the average sleep duration for babies at different ages for reference.

0-3 months 

Newborns sleep in short durations throughout a 24-hour day. As they get older, they do gradually develop a tendency to sleep more during the night. In a 24-hour period, most newborns will sleep around 12-16 hours a day but will normally only sleep for a short amount of time, in bursts. 

Unlike adults, a newborn's sleep cycle is not controlled by circadian rhythms. Before the baby is born, it relies on its mother’s physiological cues about day and night. The foetal heart rate and respiratory rate are higher when the mother is active, and slow down when the mother is sleeping. Therefore, when the baby is born, it needs to start to develop its own circadian rhythm, which can take time. 

Studies have shown that there are various factors that can cause altered rhythm development, such as premature birth, growth restriction, lighting choices in the nursery, and even when the baby is fed throughout the night, so there is not always a set timeline for a baby to develop their circadian rhythm.

When a baby is young, they really only have two sleep stages, an active one and a quiet one. During this time, they spend roughly the same amount of time in both sleep stages, while they nap throughout the day and night.

3-5 months

When your baby is around 3 months old, you will probably start to notice that your baby is more alert during the day and is more likely to interact with their surroundings. This is when they start to develop a sleeping pattern. If you are lucky, around the three-month mark babies will sleep for around a six-hour period during the night, uninterrupted.

This is a good time to start creating a nighttime routine for your baby. Routine can help soothe them and get them settled for sleep. This could include reading to them or quiet play for around 20 minutes before putting them down for bed. This can help prevent or reduce the possibility of sleep regression during this period, which can happen during this time.

When a baby is around three months old, they also begin to experience the same stages of sleep we have as adults: the three NREM stages and the one REM. Although they go through the four stages of sleep, it doesn’t follow the same duration that adults spend in each stage. Babies normally go into REM sleep almost immediately, while as adults, we don’t normally move into the REM stage until we’ve been asleep for about 90 minutes. To find out more about REM and how sleep works, check out our handy guides.

This developmental stage is very delicate. Indeed, in this period, the newborn’s brain starts developing the necessary skills to allow the newborn to become autonomous. Since sleep functions in part to promote brain development, we can study sleep cycles to understand how and why these operate more intensely during the period of life where the brain changes the most: infancy and childhood. 

It is common for some babies to go through a sleep regression at around four months old. Sleep regression is where a baby’s sleep patterns shift - they wake up during the night and find it difficult to go back to sleep. This can in turn cause sleepless nights for parents. While it may be stressful at the time, rest assured that sleep regression doesn’t last forever and is a sign that your baby’s brain is developing.

6-9 months

When your baby is around the six-month mark, they need approximately 14 hours of sleep according to various experts, but a study of 5000 American babies found that its participants slept around 12.9 hours in a 24-hour period. 

How long and the frequency of sleep in babies is found to be related to cultural differences as well as income-based reasons. This normally starts to show around this period. Different reasons that can affect sleep duration include:

• Race and ethnicity
• Socioeconomic status
• Temperature
• Diet
• Media exposure
• Gender of the child
• Physical activity

This time in a baby’s life is where they also go through a lot of development outside of sleeping, including rolling over, crawling and teething. How your baby is growing can affect their sleeping pattern, for example, if they are teething, they may be less likely to sleep for long periods of time.

Not all babies at this age will sleep the same, and there is no right or wrong way for this to happen, but it is important to try and keep their routine as consistent as possible. In some ways they’re like adults - some days they’ll want to sleep a little bit more or less than others, and it's important to learn the signs that your baby is feeling sleepy.

9-12 months

As your baby gets closer to being one year old, they start to reach various milestones at a quick rate. They start to become more mobile, crawling and pulling themselves up, and some even start walking before their first birthday. Some babies might have feeding challenges, and separation anxiety as parents start to go back to work, all of which can affect their sleep. This increase in activity can tire them out, and as they grow they can try and fight off sleep and try and hide their sleep cues, which can make it difficult for parents to notice.

It's also around the 9-month mark that the amount of time they spend in REM sleep decreases, as they start to have longer sleep cycles. Their sleep cycles will gradually get longer as they grow and by the time they are toddlers, each sleep cycle will be around 90 minutes in length.

At this time, babies need around 12.6 hours of sleep in a 24-hour period, but when they sleep can change throughout this period. As they get closer to their first birthday, their afternoon nap may become shorter, and they may sleep a bit longer at night.