Many babies will experience the 4-month sleep regression sometime around three to five months. This is a natural process as their bodies develop new skills and their sleep patterns change. For some babies, this can mean disrupted sleep and difficulty settling.
If you notice changes in your baby's sleep habits, don't worry - it's normal! You can do things to help make the transition easier for both of you.
Here we share why the 4-month sleep regression happens, how long it lasts and what you can do for a better night's sleep.
What is the 4-month sleep regression?
The 4-month sleep regression is a developmental period when your baby's sleep patterns change. Rather than a regression, your baby is actually progressing with their development because they are learning new cognitive and motor skills like rolling over and becoming more aware of their surroundings.
Not all babies will be noticeably affected by this sleep regression. For some babies, all sleep will be affected. Others may struggle in one area, i.e. daytime or night sleep, and others will have hardly any issues.
This can be a difficult period to navigate for many parents, as their baby may become fussier and cry more often. However, it is important to remember that this is a normal part of your baby's development and will eventually pass.
What are the signs of the 4-month sleep regression?
There are several signs that your baby may be going through the 4-month sleep regression. These include:
- Waking more often at night
- Crying upon waking
- Becoming fussier
- Sleeping noticeably less
- Being hungrier, with some babies starting to cluster-feed again
- Find it hard to fall asleep
If you notice any of these signs and your baby is around 3 to 5 months old, they are probably going through the 4-month sleep regression.
What causes the 4-month sleep regression?
Your baby's sleep patterns have progressed from those of a newborn to those of an infant or toddler. Their sleep cycles will now last approximately 50 minutes and contain more than just two sleep stages (active and deep sleep). Your baby will start to cycle between light and deep sleep via four sleep stages:
- N1 - light sleep
- N2 - medium "true" sleep
- N3 - deep "slow wave" sleep
- and REM (rapid eye movement) - dreaming
Your baby now spends more time in the lighter sleep stages. While they may have been fine sleeping in the daylight or with household noises in the background, they may now wake much more quickly.
How long does the 4-month sleep regression last?
The 4-month sleep regression usually lasts for around 2-6 weeks. However, there are no exact timings and it will be different for every baby.
Can the 4-month sleep regression start early or late?
The 4-month sleep regression typically starts at 4 months old however this will vary for each baby. It can start as early as 3 months or as late as 5 months. Watch out for the signs above to know when your baby is going through it.
What can you do to help your baby (and yourself!) during the 4-month sleep regression?
If your baby is going through the 4-month sleep regression, there are a few things you can do to help them (and yourself!) get through it:
- Try to stick to a bedtime routine: A consistent bedtime routine will help your baby wind down and prepare for sleep. This could include a bath, quiet time reading a book, or singing a lullaby.
- Watch out for baby's sleepy cues: Look out for your baby's sleep cues such as yawning, rubbing their eyes, going quiet or even cross-eyed, frowning, or sucking their thumb/finger/dummy.
- Keep a regular sleep schedule: Whilst, not every day will be the same, try to put your baby down for naps and bedtime at around the same time as often as you can. Wake windows for babies this age are between 90 minutes and 2 hours long and split across 3 to 4 naps per day. Each nap may last between 30 minutes and 2 hours. The day's last nap (or cat nap) is usually only 30 minutes long.
- Create a calm environment at bedtime: Make your baby’s room darker and ensure it’s not too hot or cold; 18 to 20 degrees is ideal. You can also use a white noise machine to help soothe them.
- Introduce a dream feed: It's very common for babies to be extra hungry when they go through developmental leaps. If your baby is waking more often at night, you could try giving them a dream-feed around 3 hours after their last feed. To do this, pick them up and feed them without fully waking them. You can burp them halfway, then feed them again, and if they're content, you don't need to burp them at the end. Dream feeding can help prevent them from waking early because they are hungry and should only take about 20 minutes.
Do you have a question about infant sleep? Book an appointment with one of our baby sleep consultants to receive specialist advice on any issues you may have. You can also read more tips from our experts such as getting over jet lag to managing split night sleeping.
Miriam, Sleep Consultant
Miriam is a qualified Baby and Child Sleep Consultant who feels passionately about helping other mums experience the benefits of good sleep. Her approach is gentle, relationship-centred and research-informed.