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Figuring Out the 4 Months Sleep “Progression”

So your baby was a great sleeper until they reached 4 months. “She slept so well and then those 5 hour stretches went to hourly and now I don’t know what to do, even the naps in the day time seems to have gone to pot…”

These are the words I hear often when a family get in touch with me and please know you are not alone. What is happening here is actually a wonderful thing, even though it is ever so exhausting...

It is a sign that your baby has reached a milestone and is developing and that is surely a positive thing!

When Does It Really Happen?

Any time between 3.5 and 5 months.

So What Is Really Happening And Why Is It Waking Us All Up Every Hour?

In a nut shell your baby’s brain has changed, the stages of night sleep have moved from infant to more like that of an adults. (Yes, I know we don’t wake every hour but read on…you may be surprised…!) It is a neurological progression, hence why I call sleep regressions “progressions…”

Day sleep cycles and night sleep cycles change. During the day your baby may start to cat nap, wake after only 40 or so minutes of sleep and at night perhaps every 1.5-2 hours. This may make your baby extremely tired by the time bedtime comes around in the evening it is a hurdle to overcome as your baby is going to be overtired and therefore harder to settle to sleep.

During this stage of development your baby is becoming more aware of their surroundings. They begin to focus and become a little more interested on others around them, watching big brother throwing that awesome tantrum across the room or focusing on that play gym they are trying to reach for.

Now if you have been feeding your baby every time they woke last night of course the day feeds are going to be effected and perhaps she won’t take as much and boom - reverse cycling in full swing. This causes a pattern of baby needing to wake more in the night to get those calories in.

Also if your baby is used to falling asleep with your help by feeding or rocking them perhaps, they start to really become accustomed to this methods and get hooked on them. If you are happy and it is working for you then you don't need to change this.

So What Does This Mean For Our Nights?

Well with these new adult like sleep cycles that are evolving, your baby will ever so slightly wake after the sleep cycle ends. It is a natural human behaviour to make sure we are safe, so she will be doing just that.

Now some babies may feel good about where they are at that moment and drift back off into another sleep cycle but, if your baby is not so sure, she will wake up fully and no doubt cry. She is asking you to help her back to sleep because perhaps she was not in this spot when she went to sleep. Perhaps she was having a yummy feed or being rocked or lying next to you in the bed.

She wants that back because she does not know how to fall asleep again without it. It is her safety net. Her crutch. This may happen every 1-1.5 hours through the night. And it is exhausting, I know.

You to wake at the end of a sleep cycle (if you get a chance to get that far into it…!) but you are so used to falling asleep again, you are able to drift back to sleep again and in the morning have no recollection you ever woke.

Take a look at the picture below. It is called a Hypnogram and you will see there are at least 4 opportunities a night to wake. The longer the night the more opportunities.

How to Navigate Your Way Through It

  • Make sure the stage is set for sleep. Dark room. White noise, Temp between 18 and 20.c

  • Ensure your baby is comfortable for sleep, dressed appropriately

  • They are swaddled (as soon as you see signs baby is rolling remove the swaddle and transition to a sleep bag)

  • Work with awake windows appropriate to your baby’s age and stage of development

  • Check total day sleep is appropriate to your baby’s age and stage of development

  • Give your baby the chance to fall asleep a little more on their own. You can sit with them, hold their hand and help them through it

  • Be consistent in your approach when your baby wakes if you try to get her back to sleep again

  • Know that this will pass

What Next?

Well this is a great time to start supporting your baby to fall asleep independently. If your baby is already good at this then you may sail like a dream through this progression and possibly not even notice it. But if it is causing some serious sleep deprivation in your home you can start to think about sleep training.

Gentle, loving and supportive sleep training techniques will help your child get the sleep they need and biologically require to thrive, grow and develop.

Is It Really Time To Start Sleep Training?

Yes and no! I would say you can definitely start to cultivate good sleep habits during this progression. If that is rocking your baby back to sleep and you are happy with that then go for it. There is nothing wrong with it. As long as it works for your family then there is nothing wrong with it. Please bear in mind your baby is only going to grow and get bigger though and at some point you may find rocking to sleep is causing damage to your back…

I have worked with many families whose baby was 4 months old and with a LOT of patience and time parents have reached their sleep goals. From the age of 5 months I start to implement more gentle sleep training methods. Before this age your baby’s brain is just not developed enough to learn new "sleep" skills, it is changing and we need to give it time to change and settle!

Please share this post with someone you know who also be in the thick of the 4 months sleep progression and wondering how to handle it also! It may just give them a little bit of sleep hope!

Your peaceful nights will descend upon your home soon,


Your Paediatric Sleep Consultant



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