All About The 4 Month Sleep PROgression

“My newborn was sleeping great for the first 3 months. We were getting 4, 5, 6, 7 hour stretches, but now they wake all the time!”

As a sleep specialist I hear some version of this statement frequently. I’m here to tell you that you’re not alone!

So what’s going on? Why did you have a marathon sleeper, or at least a relatively good sleeper, and overnight that’s all changed? It’s called a sleep PROgression, or even better, a developmental PROgression.


A sleep PROgression is more commonly referred to as a sleep regression. This is when your baby has been sleeping well, maybe even giving you 4+ hour stretches, and then suddenly sleep gets worse for a period of time. Sleep “regressions” often occur around 4, 6, 8-10, 12, and 18 months, and again at 2 years. Technically sleep does regress during these periods, but these changes are actually the result of your baby progressing in terms of their development. It may not feel like it, but it’s a good thing! Your baby is doing exactly what they should be doing.

You may surprised to know that there is actually no scientific evidence to suggest that PROgressions exist. Most of what we know actually comes from parent report and anecdotal evidence. During these times, parents report:

  • no longer sleeping long stretches at night
  • waking every 2 hours at night
  • short (30-45 minute) naps
  • fighting sleep
  • increased fussiness
  • baby is “clingy”
  • frequent feeding
  • strategies and comfort measures that used to work are no longer working

However, each baby is unique and each baby will differ in their experiences. Some may:

  • have trouble with naps
  • have trouble with night sleep
  • have trouble with both
  • have no trouble at all
  • take longer to work through it
  • take no time at all


Around 4 months, give or take, your baby undergoes a lot of developmental change that can interrupt sleep. Your baby:

  • Is essentially waking up to the world and no longer has that newborn stimulus barrier that allows them to sleep through anything. They are also more aware of their surroundings and may be more distracted, which can make it hard to fall asleep and stay asleep.
  • Has more organized sleep cycles, which are similar to an adults. Initially, when your baby fell asleep they fell into a state of active sleep followed by quiet sleep, and they cycled through these two stages. However, around 4 months, your baby begins to cycle through all 4 stages of sleep, which is new and can be unsettling.
  • Is working on new skills like rolling, hand-eye coordination, holding objects, and language.
  • May be cutting their first tooth or teeth.
  • May be working to increase your supply if you are breast/chest-feeding. Up until now, your supply was driven by hormones and relatively stable. However, your supply is now based more on supply and demand. If your baby had been sleeping long stretches they may not have been removing enough milk to meet their needs and are now trying to regulate your supply. You may notice that your baby wants to nurse more at night when your prolactin levels are high, which means more milk! As well, having an oral restriction (i.e., tongue tie) may also produce the same results.


This is a really tricky time for parents. I know, I’ve been there. However, there are some things you can do that may help make things easier:

  1. If you are reading this and have not gone through this PROgression yet, my biggest advice is to build in numerous sleep associations and comfort measures. A sleep association is anything your baby associates with sleep. For example, nursing, shushing, patting, rocking, singing, white noise, sleep sack…The more associations you have, the more tools you have in your tools you have in your toolkit to comfort your baby and to get through this stage. If you are reading this while in the midst of the 4 month PROgression, it never hurts to start adding in numerous sleep associations at any stage. However, you may benefit more from doing whatever works right now. This might be a using motion (i.e., stroller, car ride, rocking), contact (i.e., carrier, in arms), or nursing/pacifier. I promise it will pass.
  2. If you are nursing, rule out any supply issues, latch issues, and/or oral restrictions. Your best bet will be to consult with an International Board Certified Lactation Consultant (IBCLC).
  3. Engage in self-care and ask for help. Remember, this is a difficult time for parents and babies. You can’t pour from an empty cup and you will need to put your oxygen mask on first in order to better support your baby. No seriously, don’t skip this part. If you’re stressed, your baby will mirror these feelings back to you. It’s called “mirror neurons.”
  4. Tune into your baby and note your baby’s unique sleepy cues and wake windows. It can be helpful to log your baby’s daytime and nighttime sleep for 5-7 days and note any patterns.
  5. Give your baby lots of time to practice any skills they are working on during the day. There are a lot of great Instagram accounts and Youtube videos created by occupational and physical therapists that show you how to support your baby’s development based on their age. If you are concerned about your baby’s development or they aren’t meeting their milestones, please reach out to your doctor or find an occupational or physical therapist in your area.
  6. Implement strong routines (not schedules). You can learn more about routines and schedules here.
  7. Don’t make any big changes. If you had things that were working for you before, they may just work for you again. Give it time and trust your instincts.

Mama, I know you’re tired. I know it’s hard, but I promise it will end! If you’re in need of more support, I have created a PDF guide that gives you all you need to know about the 4 Month sleep PROgression and how to make it through. You can learn more here. As well, please don’t hesitate to reach out if you are in need of more one-on-one support!

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