What Is Sleep Regression? A Guide to Understanding Your Baby’s Sleep

Simply put, it is a period of time when your baby sleeps poorly after having slept well. It is normal, predictable, and we can help with tips to make it easier.

By Sheryl Grassie

Sleep regression is when your baby starts waking at night or having a hard time napping after previously sleeping well. But don’t be afraid, sleep regression is a normal process that happens in relation to developmental milestones. It can be challenging and feel like it comes out of the blue, but it is temporary. 

What You Need to Know About Sleep Regression

Baby crying

4 months, 8 months, 12 months, and 18 months

There are common sleep regressions that can happen around the ages of 4 months, 8 months, 12 months, and 18 months, but not all children will experience all of these, and some children don’t experience sleep regression at all. Sleep regression can be fairly short lived and last a week or two, or it can be more prolonged and stretch out for five or six weeks. It may also happen before or after the average, for example, the 4-month regression can hit anytime between 2 and 5 months and still be part of a normal developmental process. 

The 4-Month Regression

Around your baby’s fourth month is the most common time for a sleep regression. They may, out-of-the-blue, stop taking a nap, fight going to sleep, or be up and down all night. This behavior can be an indicator of other physical maladies, and of course, it bears getting your little one checked out if you are really concerned. However, if nothing else seems wrong, it may just be the end of their first developmental period, that of newborn, and the beginning of a new infant phase.

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When this shift occurs, somewhere around the 4-month mark, there is a period of stepping back before stepping forward, as if to gather momentum. This step back, in the form of regressed sleep, is a natural way of amassing energy for the many changes and tasks that will take place during this next stage, including rolling over, sitting up, and incorporating solid foods.

One of the things that will happen after four months is your baby will solidify a lifelong sleep pattern that will stay in place indefinitely. They will progressively sleep less, but the rhythm of sleep will stay the same from this point on. If you have an early to bed, early to rise baby after the 4-month period, they will likely stay that way into adulthood. The same is true with their patterns of being tired, awake, and asleep.

Another developmental aspect of the 4-month regression is your baby’s change in sleep cycles. Humans have four stages of sleep that cycle throughout the course of the night. These can be split between the first 3 stages of non-REM (rapid eye-movement) sleep and REM sleep

Everyone has these periods of light and deep sleep that last about 90 minutes and then start over in a continuous cycle. You begin in light sleep, stage 1, progress to stage 2, and then to the deep sleep of stage 3. These periods of sleep focus on repair and restoration of the body. Then you enter into REM sleep, where the focus is on the brain and memory function among other things. 

Newborns split their time almost equally between light stage 1 sleep and the deeper REM sleep. At around 4 months, they incorporate the remaining two sleep cycles and begin the full adult rotation through all 4 cycles. When this change is taking place, it can disrupt sleep and cause sleep regression. 

Tips to Help Ease the Challenges of the 4-Month Regression

    • Focus on the excitement of the new skills your baby is gaining
    • Keep them in a consistent bedtime routine
    • Use weighted blankets or weighted sleepers to help soothe them
  • Work on ending sleep dependencies. Have them go to sleep without the help of nursing, rocking, or a pacifier
  • Manage the sleep environment by keeping it dark, quiet, and a comfortable temperature at 70 degrees 
  • Add more food to your baby’s diet, either by nursing more often or adding in solids

The 8-Month Regression

Another common sleep regression can happen around the 8-month mark. Sleep patterns can change once again as babies experience a host of new development skills that likely have them spinning. There are new physical competencies taking place like crawling and pulling up to standing that give your baby dramatically increased physical independence. Their bodies are changing and growing at an accelerated rate, and they may be getting their first teeth. 

Also, this is a period of rapid brain development, and your baby is now perceiving the world in a much-expanded view, they are understanding new words and concepts, taking in new experiences, and learning to think independently. Some more precocious babies will start to experience separation anxiety around this age, and that too can interfere with sleep. All these tasks require energy that can cause sleep disruption. It usually only lasts a few weeks, but sometimes up to a month or more. 

Tips to Help Ease the Challenges of the 8-Month Regression

  • Be patient and take care of you!: This means getting enough sleep, asking for help, and doing things to de-stress like exercise, meditation, or a nice hot bath.
  • Rule out other sleep problems: If your baby’s change in sleep pattern is more sudden, then it is likely a sleep regression. If, however, it has lasted for months or been intermittent at 5, 6, even 7 months, then it may be a different problem.
  • Practice of new skills: Babies need to practice the new skills they are learning. If they don’t get in enough practice during the day it can cause them to wake at night. Give them plenty of opportunity to crawl and move around, and keep their brains engaged with active exercises like puzzles and blocks, sorting games, and books. 
  • Get enough daylight: Sleep is regulated by exposure to daylight. Getting your baby out to the playground, a park, or for a walk, preferably in the morning, is a great way to help them sleep better. 

The 12-Month Regression

This is a less common time for a sleep regression, but it does happen. Separation anxiety can be high at this point, babies are learning to walk, and talk, and to see the world from an upright vantage point. They are also getting more teeth which can be painful. Their developmental tasks continue at a rapid pace and sleep can be disrupted.

It is common for the sleep challenges to center around naps at this age. Babies may be going down to one nap a day in the coming months, and they may start skipping either their morning or afternoon nap at this point. Try some of the tips below for regulating their sleep, and see if they can’t continue those two-a-day naps for a few months longer.

Tips to Help Ease the Challenges of the 12-Month Regression

  • Keep a consistent bedtime and naptime: Routines and consistency help tremendously for both babies and adults in getting good sleep. Put baby down at the same time daily for both naps and bedtime. 
  • Get enough daylight: Again, sleep is regulated by exposure to daylight. If you keep your little one primarily indoors, they won’t produce enough sleep hormone to get them through the night. Get them out for as much fresh air and sunshine as you can manage. Morning light is best.  
  • Practice of new skills: Your baby is almost a toddler, and the toys and activities that engaged him or her just a few months ago will need updating. Make sure your child has the opportunity to practice their new skills both physically, with walking and moving around, as well as mentally with new levels of books and puzzles; new challenges. Adequate daytime engagement translates to better sleep.
  • Get enough exercise: You will notice your child has lots of energy at 12 months and they need an outlet. This is a great time to engage in baby swim classes, toddler gym activities, and anything that gets them moving. Put on some music, and let them dance as best they can. All that energy expenditure will result in better sleep.
  • Mitigate any pain: If teething is an issue, try numbing teething rings or an oral analgesic to calm the pain.

The 18-Month Regression

This one is often described as the hardest of the sleep regressions. First, it is not a guarantee that your child will have issues with sleep at this age, but many do. And, when they do, their newfound level of skill and independence can make them very willful and difficult. They understand the concept of “no,” and can use the word liberally at this age. Pushing back is part of their development, but it can make it hard to intervene and get them on a good sleep schedule. 

By this point, they are almost definitely transitioning down to one nap, and you may need to support that change rather than fight for more than one. Also, they naturally need less sleep as they age, so a later bedtime or earlier wake up time may just be a natural part of their growing up. If sleep is challenged overnight practice good sleep hygiene, and see your physician if you need additional help.

Tips to Help Ease the Challenges of the 18-Month Regression

  • Enough daylight: Again, since light regulates our sleep, more time outdoors or in a sunny window, early in the day can really help with sleep. The goal should be an hour of unfiltered daylight to help your child produce enough melatonin (the sleep hormone) for good quality sleep.
  • Sleep hygiene: There are a host of do’s and don’ts when it comes to easily falling asleep and staying asleep that can be applied to your little one.
    • No snacking after dinner, or very light food; aim for no eating for at least 1.5 hours before bed. 
    • No screen time, iPad or TV, at least 2 hours before bed
    • Maintain a consistent sleep schedule, put your child to bed and have them get up at the same time daily 
    • Have them get plenty of fresh air and exercise
    • Do something relaxing with them before bedtime like a bath or reading in bed
    • Reduce household lights in the evening!
    • Have them sleep in a dark, quiet, comfortable temperature room, using room darkening curtains if needed
    • Use lavender. Put the oil in a diffuser, on a pillow, or in their room: the smell helps with sleep.


What is sleep regression? The term refers to a period of troubled sleep for a young child who has been sleeping well. Sleep regressions are perfectly normal albeit challenging and can occur in tandem with developmental milestones. Most sleep regressions will just have to be weathered, but there are things you can do to mitigate the intensity and help your child sleep better. There are predictable developmental points starting around 4 months that can disrupt sleep. Appreciate that your child is growing and changing, and trouble sleeping can be a normal result.

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