July 22, 2023

The 4 Month Sleep Regression

The 4 Month Sleep Regression

This has to be one of the most common things people think of when they think of baby sleep, and when you’re a parent who has been warned of this disastrous regression, it can feel like a dark cloud looming just ahead.


This regression happens when your baby’s sleep cycles mature from a straightforward newborn sleep cycle, that is made up of only light sleep (REM) and deep sleep (nREM) into a more complex sleep cycle similar to that of us adults.

This new sleep cycle advances to one made up of 4 different parts and now has a definite beginning and end.

This means that now your baby won’t be drifting through from light sleep to deep sleep back to light sleep any longer, and now needs to go from awake, to drowsy, to light sleep, to deep sleep, back to awake and start the process again.

This regression can be experienced anywhere between 3 - 6 months of age!


There is a few distinct signs that can announce the arrival of this dreaded sleep regression.

  • Catnaps: If your little one used to enjoy some nice naps and almost instantly has started taking cat naps that end like clock-work, there’s a good chance the regression has arrived.
  • Frequent night waking: You just got used to some longer overnight stretches and now your baby is waking up. Every. Two. Hours. Overnight their new sleep cycles are commonly grouped into blocks and we typically see the disruptions every 2 hours.
  • Difficulty falling asleep: Rocking to sleep may suddenly take much longer that typical and may seem to need more assistance to get to sleep.


Somewhere between the age of 3-6 months, ALL babies will go through this permanent neurological change and transition from newborn sleep cycles to the adult like cycles mentioned above.

However, this is not to say that all babies will see the drastic effects that can come from this development.


This regression typically does last several weeks, it is also a really great time if you are wanting to work toward independent sleep to start looking into this option now.

During this time, your baby's vision improves and they also become significantly more aware of their environment.


Sleep associations can start to form between 4-6 months - these are what your baby associates to the falling asleep process such as rocking, feeding or patting to sleep and for some babies these can be disruptive to sleep contributing to sleep battles, frequent night waking and catnapping.

It is important to remember that these are NOT "bad habits" - this is something we don't believe in here at The Sleepy Little Bubs because if it works for you, keep going!

However, if what you are doing is no longer working or sustainable, it's OK to make changes that work for you, your baby and your family. 

    • For small tweaks to routine, have a look at our Quick Chat - 15min  option
    • For parents struggling with several things such as catnapping, frequent night waking, early morning rising or things that simply no longer work, have a look at our Phone + One Week Support option.
    • Not sure what is right for you? Get on the phone to one of our experienced consultants with our FREE 15min Discovery Call