How Long Does the 4-Month Sleep Regression Last?

Just before my first baby turned 4-months I was constantly warned about the horrors of the 4-month sleep regression. I anticipated the long nights of a baby who wouldn't sleep or nap, leaving me shattered by morning. But, I did my research, followed sleep advice - and you know what? It wasn't that bad. I've got everything you need to know about the 4-month sleep regression below.

What is sleep regression?

Sleep regression is when your baby or toddler's sleep pattern suddenly changes for the worse. They refuse to nap, have trouble falling asleep, or experience frequent nighttime wakings not typical of their previous behaviour. But how long does a sleep regression last? And is there anything you can do about it? Find out below.

How long does the 4-month sleep regression last?

How long is a piece of string? No, but seriously the 4-month sleep regression can last anywhere between 2 - 6 weeks (or sometimes more).

Sleep regressions typically last a few weeks or months.

You can expect the regression to start when baby is 3-4 months old and how long it lasts depends on how quickly your baby adapts to the adult sleep cycle, gets through teething and other developmental leaps and any other factors that may be disrupting your baby's sleep. We have some tips in the next section on how to deal with the sleep regression, which may help your baby adapt to this new challenge a bit more quickly.

Why do babies and toddlers have sleep regressions?

There are lots of different reasons your baby or toddler may experience a sleep regression. Some babies go through sleep regressions because they have achieved an important milestone, such as sitting up, crawling, or walking. Research indicates that babies learning new motor skills can be disruptive to sleep as their little brains are so focused on developing these skills, making them restless. The 4-month sleep regression is a common period for this, as their adult sleep cycles begin to develop, language skills expand, and they get an increased awareness of their surroundings.

Other reasons for sleep regressions include teething or growth spurts and the development of separation anxiety, which means your baby may now start to feel more distressed when they are away from you.

How to cope with the 4-month sleep regression

Below, we've outlined our tried-and-tested techniques for dealing with a dreaded sleep regression:

A strict sleep routine

Babies and toddlers thrive on routine, especially when it comes to sleep. Your bedtime routine could look like anything, as long as it's calm and relaxing, and you stick to it every night. At four months, our routine was very simple: A bath (although we don't do this every night), a clean nappy, pyjamas and sleep sack, a bottle, a cuddle, and bed. Some parents also like to dream feed their baby to encourage them to have a longer stretch of sleep.

A cosy sleep routine can help get baby settled for the night.

For our toddler, we eventually swapped out the bottle for her water beaker and added in a bedtime story. We would start the routine at the same time every night, stop any music or overstimulating activities at least thirty minutes before and dim the lights.

Tip: You should ensure the bedroom is cool and dark (the ideal temperature is around 18°C) and make sure the baby is dressed appropriately - not too hot or cold.

Monitor their amount of sleep

Babies who are getting too much sleep during the day will have difficulty falling asleep at night. By following appropiate wake windows you can ensure your baby has just the right amount of sleep throughout the day to help them settle better at night.The amount of sleep a baby needs changes as they grow, so it's important to be aware of how much sleep your baby needs at their age.

Keep track of baby's naps and how much sleep they're getting.

If they keep waking throughout the night, this could be a sign their sleep tank is already full, and you may need to drop a nap during the day. You should also make sure your baby doesn't sleep too close to bedtime. Our 6-month-old baby sleeps better when he has at least 2-3 hours between his last nap and bedtime. Likewise, not enough sleep can have a similar effect. The Lullaby Trust has some solid advice on how much sleep your baby needs for their age.

Co-sleep if you're struggling to stay awake

If your baby's sleep regression is leaving you exhausted to the point you're afraid of falling asleep with your baby, consider co-sleeping following safety guidelines. This is often safer than accidentally falling asleep with your baby as you can prepare in advance to make sure the area is as safe as possible for your little one. This means no bedding or pillows near your baby, no other children or pets in the bed, and not co-sleeping if you have smoked cigarettes or drank alcohol. You can find all the co-sleeping guidelines on the Lullaby Trust website.

Baby sleep Regression Ages Chart

Guess what? It's not just the 4-month sleep regression us exhausted parents have to contend with. Nope. You can expect similar sleep regressions all the way up to 2-years-old. The table below gives you an idea of each sleep regression age and what to expect.

how-long-does-the-4-month-sleep-regression-last

Age	What’s Happening	Why Sleep Changes
4-Month Sleep Regression	First major sleep regression - this is the big one!	Baby’s sleep matures into cycles similar to adults
6-Month Sleep Regression	Increased movement and development	Growth spurts and milestones like learning to sit up and crawl
8–10 Month Sleep Regression	High developmental leap	Separation anxiety, crawling, pulling to stand, and teething.
12-Month Sleep Regression	1-year sleep slump	Toddlers start walking and developing language, which can reduce sleep needs.
18-Month Sleep Regression	Big emotional + physical changes	Teething (first molars), separation anxiety, and becoming more independent.
2 Year Sleep Regression	New awareness and toddler sleep challenges	Nap refusal, separation anxiety, and fears like the dark or nightmares.

To summarise

Sleep regressions are a natural part of your baby's development and trying to prevent them will just make things worse. Instead, follow your baby's wake windows, follow a calm bedtime routine and remember, sleep regressions don't last forever! It may feel like it's just your baby who is going through a dreaded sleep regression, but trust me, we've all been there and come out the other side.