Nothing strikes fear in the heart of parents more than a sleep regression.
No, I'm kidding, but it's no fun to deal with for sure. Baby wakes up more, spends longer stretches awake (read: up to several hours), and often it keeps parents up more than they really want to be. They often happen around the same ages - 4 months, 9 months, 12 months - or, they can happen because of teething, growth spurts, etc.
Now, as tough as they can be to deal with, it's a very good sign that your baby's brain is making very important changes!
I always have found it very interesting that the typical "sleep regression" ages also seem to coincide with certain milestone gains. 4th month regression? Your baby is starting to see details, rolling and creeping. 9th month regression? Your baby is babbling their heads off and crawling all over the place! 12 month regression? This is when babies are starting to take their first steps and say their first words. Pretty incredible, right? And of course their sleep is going to be thrown off - their brain is making sure that all these new skills are permanent. It won't rest until these new milestones are perfected!
There are also pretty significant changes when it comes to sleep needs as well. The biggest one is at 4 months - this is a time that the brain is maturing and more steps are added to your baby's sleep cycle. Up until this point, babies only have 2 stages of sleep - stage 3 (deep sleep) and REM (rapid eye movement, not so deep) sleep, and spend equal amounts of time in both. By 4 months, 3 new stages of sleep develop and a baby's brain needs time to adjust to these changes.
The problem is that for most babies, they have been used to going to sleep while feeding, getting rocked, etc. When different stages of sleep are added to the mix, it becomes significantly harder to get them to settle for the night. Let's take a fairly typical scenario - Mom is settling baby and rocking them before laying them in the crib. Baby starts to nod off and mom decides to carefully put baby in the crib. Baby is aware that the situation is changing and naturally, they don't want mom to leave! So as mom lowers baby down, they start to cry and wake up. They don't want that rocking to end! Effectively, the reset button has been pushed and mom has to start the whole process over again. Best case scenario, baby stays asleep, but don't be surprised if baby wakes again after an hour - They went down with mom, and now they're all by themselves. That can be a pretty startling thing to a baby! When baby's sleep starts off significantly lighter than it did before, it becomes a lot harder to get them to settle.
So, regardless of when a "regression" happens, what can you do about it to make the adjustment as easy as possible?
1) Make the room pitch dark. This alone can make a huge difference in extending sleep because there's no outside influence waking your baby up. Not sure if your baby's room is dark enough? If you can still see your hand extended in front of you even after putting up black out blinds and such, it's still not dark enough. Try taping dark paper or using window covers to keep it pitch black.
2) Keep feeds closer to the time your baby has woken up from sleep, not before they go down. This allows baby to get the full benefit of the feed, and avoids a feeding to sleep association.
3) Establish a really consistent bedtime routine. By following the same activities leading up to sleep, your baby can start to predict that it's coming and it makes it a lot easier for them to settle. Some activities include a bath, reading a story, singing a song, and more.
4) Avoid putting your baby to sleep overtired. Know how long your baby can tolerate being awake and put them to sleep ahead of getting irritated and cranky. Here's a quick guide:
These recommendations can help a baby of any age with getting through any sleep "regression." But, anything that parents can do to encourage their babies to go to sleep independently will help to avoid big disruptions down the line.
So, embrace the regression! Know that your baby is making big changes in their development and take a sigh of relief. It will take a little time to work through, but things will settle soon enough.