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 hours overnight
And can start from anywhere between 3 to 6 months old.
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
What causes the 4 month sleep regression?
(or 4 month sleep PRO-gression, as it's not always a ‘regression’ in sleep) 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. They go from newborn sleep cycles to more adult like sleep cycles. 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. So if a baby relies on a strong external sleep association to be able to fall asleep, they will also now need these things returned at the end of every sleep cycle to be able to go back to sleep.
Which is why your baby might be suddenly waking more overnight and only having short naps.
Read how this 4 month old went from waking every 2 hours to sleeping through the night here.
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.
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?
Because this regression is driven by a permanent biological change in your baby’s sleep cycles, it doesn’t really ‘end’ in the traditional sense. Their sleep cycles themselves have matured and won’t return to the newborn structure. To get consistently great sleep again, and to have your baby start linking their own sleep cycles, you'll want to first work on helping them gain confidence in falling asleep more independently at the beginning of sleep times.
Feeling lost on where to start? Grab our Baby Sleep Program for a gentle step-by-step plan to get your little one's sleep on track. You could all be sleeping soundly in a matter of days!
