4 month sleep regression signs

4 month sleep regression signs

Wondering whether you've hit the dreaded 4 month sleep regression? The most common signs of the 4 month sleep regression are:

  • becoming harder to settle to sleep,
  • having only short 30-45 min naps, 
  • distracted & fussy during day feeds,
  • waking every 2,3 or 4 hours overnight...

And can start from anywhere between 3, 4 to 5 months old. 

What causes the 4 month sleep regression?

(or 4 month sleep PRO-gression, as it's actually not a ‘regression’ at all). During the newborn months, once you’ve established a good feeding and nap rhythm you can start to have great long stretches of night sleep. A newborn baby's sleep cycles aren’t well defined and sleep phases disorganised, which means they can easily pass from one sleep cycle to the next without fully waking. With great sleep foundations in place, by 3 months many babies can be sleeping 11-13 hours overnight, just waking briefly for a quick feed or two.  

But at around 4 months babies go through a huge shift in sleep biology. Their sleep cycles are now separated into four phases (ranging from light to deep sleep, and active sleep) and there’s a distinct line between the end of one sleep cycle and the next (a pattern that lasts for the rest of their lives). Which means they now start to wake fully between every sleep cycle. 

These wakings between sleep cycles happen every 30 to 45 minutes during day sleep, and range from 2-4 hourly overnight. Which is why your baby might be suddenly waking more overnight and only having short naps.

Should you feed at night wakes during the 4 month sleep regression?

There is a growth spurt around this time, so for babies that were sleeping through they may start to wake for an extra feed in the night. But they should still only need one to two overnight feeds at this age. If they are waking more than this, it's likely just because they are looking for assistance to get back to sleep between sleep cycles. If you have been feeding at every wake, they may begin to 'reverse cycle'. This means they start to take less milk in during the day, and then wake in the night to catch up. Read how we helped this family go from several wakes to feed at night to one in just 7 days. 

Do all babies go through the 4 month sleep regression?

Yes, as it is a biological change to sleep patterns. But if your baby knows how to fall asleep independently you might not experience a disruption to sleep. You may just start to notice them wake from a sleep cycle and shift position a little, as they (subconsciously) check their surroundings to ensure everything is ok and the same as it was when they fell asleep and then get themselves back to sleep. These wakings are completely normal and are a survival mechanism that even as adults we carry out every night.

But if a baby relies solely on parent assistance, or say a pacifier or bottle, to initiate sleep then they can also struggle to fall back to sleep between each cycle without that same assistance.

How long will the 4 month sleep regression last?

Some babies adapt quickly to the change, and start sleeping well within a couple of days! But if it’s been weeks or months of disrupted sleep, it probably means your baby needs a little assistance to help them start to link those sleep cycles again. 

Feeling lost on where to start? Book an online sleep support package for a personalized step-by-step plan to get your little one's sleep on track. You could all be sleeping soundly in a matter of days!


Is your baby sleeping relatively well but then waking for a long period overnight? You might be experiencing a split night, read more about split nights here