Dr. Sarah Mitchell
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July 1, 2020

4 Month Old Baby: Here is What You Need to Know as a Mom

4 months in the baby sleep world is often known as the end of the 4th trimester.  After those first 3 months of life, your baby is now waking up the world around them.  They are engaging in eye contact with you, laughing and sometimes learning to roll.

At this time the startle reflex has usually disappeared although your child still likely lacks strong arm control.  This is often seen with the arms immediately stretching out overhead when coming out of the swaddle. 

Signs of the 4 Month Old Sleep Regression

Between 3.5 months and 4.5 months a child will start the 4 month old sleep regression.  At this time I often hear from parents who are dismayed that their little one who used to sleep 6-8 hours at a stretch at night is now waking up every 3 hours.  In addition, their naps seem to becoming shorter.

The Signs of the 4 month sleep regression

  • Waking up more frequently at night - often every 3 hours
  • Shorter naps - often 45 minutes in length

The first question parents ask... "How long will the regression last?" Well that depends.  It depends on your child's existing sleep skills and your baby's temperament. Students in my Newborn Sleep Class will have developed some independent sleep skills already and usually wake up less at night than babies who are completely dependent on their parents to put them to sleep.   The regression is due to progress.  Your child is learning object permanence.  The fact that you exist even though she can't see you and cries for you more to test out this premise. You always respond to help them establish that concept. Some parents can seem to "get back to normal" after a couple of weeks where other parents continue to struggle, nursing, rocking or reinserting the pacifier every 3+ hours in the night.

You can read more about the 4 month sleep regression here.

How Much Sleep Does a 4 Month Old Need?

When working with a parent or in my online sleep school, our goal is to get a 4 month old this much sleep:

  • 11 hours of overnight sleep with 1-2 night feeds depending on food source
  • 3-4 hours of daytime naps 
  • Total 24 hour sleep ~15.5 hours 

If your baby isn’t getting this you might be seeing frequent night waking, short naps.  A tired baby is harder to get to sleep and stay asleep.  You get stuck in a negative feedback loop of lacking sleep and having to work harder to get it.

You might find this blog post on 5 Signs Your Baby is Overtired to be helpful.


How to Get My 4 Month Old to Sleep

When I was going through this personally, I expected sleep to be this easy natural thing.  So I was shocked when I continued to be waking up every 3 hours in the night at 4 months of age. 

The drive to sleep is biological, but the way we sleep is a learned habit. - Dr. Sarah Mitchell

Sleep is a learned habit.  Overtime your baby associates with sleep in a certain way.  For many of my clients this looks like rocking to sleep, dozing to sleep on the bottle or co sleeping.   All humans wake in the night, so when your baby wakes she looks for those same conditions to fall back asleep.  We call those conditions her sleep crutches. 

Sleep crutches include:

  • Motion:  rocking, stroller, carrier, car seat naps
  • Sucking:  Pacifier, bottle, nipple
  • Touch: co sleeping, carrier naps 

The one thing you can work on without tears is the timing of sleep.  Making sure your baby is asleep within 1 hour and 45 minutes of being awake at 4 months of age.  After this time it can be harder to get her to fall asleep and then stay asleep.   This includes bedtime. 

From there, you might have to do some “sleep training” or as I prefer to call it “sleep teaching.”  Sleep is a learned habit so you’ll have to really do sleep unlearning.  Changing the way she falls asleep without those external things that she associates with sleep. 


In my private high touch 1:1 consultations or my online sleep school I teach you step by step how to offer comfort to your child and set her up for success as you change the way sleep looks to her.  Both programs offer a level of support from me because every baby is different and you’re going to have questions while you move through your journey. 

Click here to learn more about Helping Babies Sleep School, the online classes and Private Facebook Group Support. 

Read More

4 Month Old Sleep Schedule

What You Need To Know About Sleep Training Vs Sleep Teaching

Why Newborns Babies Are Fussy At Night? What Causes It | EXPLAINED


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