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4 month sleep regression - What really happens to baby’s sleep at 4 months?

Baby rubbing eyes asleep at 4 months sleep regression

4 month sleep regression - What really happens to baby’s sleep at 4 months?

Baby’s sleep goes through a huge change around 4 months, although this change can actually occur at 3 months or 5 months as well. The change is typically described as the 4 month sleep regression, but what exactly is this sleep regression and what does it mean for babies (and parents sleep) and what can you do about it?


The 4 month sleep regression is actually a progression in babies sleep and their neurological development. Prior to this your baby’s new-born sleep phases were deeper and they more easily drifted from one cycle to another. Once they hit this milestone around 4 months, they now have lighter phases of sleep and rouse fully in-between sleep cycles.

Baby dressed in white sleeping in cot


The length of a sleep cycle is 40 minutes during the day and 2 hours at night, which means they will be waking this frequently at night and catnapping during the day.

Sleep associations can make this period of time more difficult. During the newborn days if you fed, cuddled, rocked, held or assisted to sleep in any way it wasn’t an issue as baby would naturally sleep longer chunks. Once they go through this change they are now looking for that assistance at each wake. This is why it’s so exhausting because you are now needed multiple times at night and through the day.


So what can you do? Well if you’re assisting to sleep you’ll might want to stop and consider starting to teach self-settling. To teach self-settling there are a few things you can do.

  • Don’t rush in, give them the chance to settle themselves. If we rush in before they have even woken up properly they will never learn the skill of putting themselves back to sleep and sometimes we’re assisting when they don’t even need it.

  • Find a method that you’re comfortable with and that suits the temperament of your child, this may be in the room, out the room, using touch or not. It really does depend on what works for you as a family. Be consistent and use that to teach them to settle themselves and re-settle. It can take 2 weeks but if you’re consistent and follow through you’ll see changes with your baby quickly sleeping longer chunks at night and learning to link those day sleep cycles past 40 minutes.

  • If they are having multiple feeds but of a healthy weight and thriving, drop down to 2 feeds one being around 10/11pm (can be a dream feed) and one around 2/3am. Use your settling method in-between those wakes to get them back to sleep.

4 months is a great age to teach this skill, they are now biologically ready and it will help with avoiding the repercussions of the later regressions down the line when they turn 8/12/18 months. Teaching them this skill now instead of waiting until they are a toddler is much easier.


Unfortunately this isn’t just a phase that will go away and it’s one that can wreak havoc for the entire family. Knowing how to spot it and what you can do will help you to respond in the best way possible to ensure everyone is getting the sleep they need.


This guest blog was written by Karen Miller, mother of two and Certified Baby Sleep Consultant working with newborns though to children age 5.

You can connect with Karen on her social media channels (Facebook, Instagram and YouTube) and can book a FREE 15 mins call with her here


Four months is a time when you might be starting to think about weaning and looking for the signs that your baby is ready for their first solid foods.

If that's you then you're at the perfect stage to sign up for my next online baby weaning workshop! We'll spend time chatting about the signs to look for, what foods are good to introduce first, how to safely prepare food for your baby, and anything else you need to feel confident about your weaning journey. To find book your place, head over to the online weaning workshop page here.

4 month baby sleeping baby sleep regression ready for solid foods and weaning


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