What is a Sleep regression?

sleep training baby

As if parenting and baby sleep wasn’t difficult enough, just when thinks might be looking up, a darn sleep regression comes along and rips it all up. Soul-destroying isn’t it?

Your baby’s sleep might be amazing (sshhh don’t tell anyone) or it might be manageable. Your bedtime routine is good; your baby or toddler will fall asleep more smoothly than they used to; and the one night, your sleep problems are much worse for the next few weeks? The difficult bedtimes return; the multiple and frequent night waking, the cat naps. What the heck has just happened? A sleep regression; three words that send a shiver down most parents’ spines.

For those of you who have babies that always struggle with poor sleep, fighting sleep, the night wakings every single night and all you ever hear from friends is “it’s probably just a sleep regression; don’t worry it will pass soon enough. But someone told you that last month… and the month before that…. and the…. you get the drift. So was it a sleep regression or not? How do you actually know if it’s a sleep regression or just generally poor sleep patterns that need fixing?

I am a leading sleep consultant in Ireland, and in this article I will help you understand what causes sleep regressions, how to know if it’s a sleep regression you’re facing or just bad sleep, how long they last and my top tips to survive them.

The Daddy Sleep Consultant - Chris posing for a photo


A sleep regression is when a baby reaches a new cognitive or physical developmental milestone which often impact sleep due to the way that babies handle these new developments.

Out of nowhere, a baby may fight going to bed when they’ve been able to self-settle prior to then. They are likely to show extra levels of fussiness whenever they are put into their sleep space and you may see more wake-ups than normal, resistance for naps and cat naps of 40-45 minutes.

Below are the big developmental milestones which are likely to lead to a sleep regression:

  • Sleep physiology change where babies start sleeping in cycles (4 month sleep regression)
  • Learning to roll, stand, crawl or walk
  • Development in their language, even it’s not necessarily audibly different
  • Separation anxiety
  • Transition to more independence

Other big changes can impact a baby’s sleep patterns:

  • Being unwell
  • Increase in teething pain
  • Dropping a nap
  • Starting creche or with a childminder
  • Parent(s) returning to work

Sleep regressions will and do happen – you cannot do anything about them happening. However, you can try to avoid starting sleep habits that you don’t want in the long-term. Let me explain how.

baby yawning whilst being swaddled


The signs vary from child to child. Not all babies will show the same signs of a sleep regressions, but the below is a list of what most babies will show during a regression:

  • Difficulty in falling asleep at bedtime
  • Infant stops self-settling
  • Frequent wakings in the night
  • Resistance to naps
  • Cat naps no longer than 45 mins
  • Mood has changed; more cranky and grumpy


A sleep regression can last anything from two to six weeks but in my experience, it’s usually closer to the former time frame of two weeks. So if your baby feels like they’re going through a sleep regression for 2 months, then it’s not likely to be the regression any longer but sleep habits you may want to change.

My affordable online sleep training courses can help you make long-lasting changes and improve your whole family’s well-being in the space of just a couple of weeks.


This is probably not the news you want to hear (!) but sleep regressions can, and do, happen at any age as children develop at different rates. And given that the driver of a sleep regression is usually developmental milestones, this can mean sleep regressions happening at different ages for different babies.

However, the most common and well-known sleep regression ages are at 4 months, 8 months and 18 months. Here are the main reasons for each of these:


Find out more about the 4 month sleep regression in my article here.


The next big sleep regression after the 4 month one is the 8 month sleep regression. The developmental milestones that occur around this age and drive this sleep regression is:

  • Development of separation anxiety
  • They are learning to crawl or stand up
  • Teething is back with a bang!
  • They are transitioning to 2 naps and longer awake periods


A big reason for the separation anxiety developing is the gradual arrival of object permanence which becomes more evident around the 8-12 months mark. This development is where a child’s ability to know that objects will continue to to exist even though they can no longer see or hear them; for example when you leave the room.

baby with blue eyes lying on back looking to the side

Another big factor in the 8 month sleep regression is the transition of a baby’s nap schedule. They will start to stay awake for longer periods – around 2.5 hours after good, solid sleep – and will typically drop from 3 naps to 2 during this period.


This is the toddler sleep regression which generally occurs because of your little baby developing into a toddler and wanting to be more independent. As sad as that can be for us parents, it’s lovely watching them want to do more things (albeit the tantrums can be spectacular!). Their language is also rapidly developing and their understanding of what you are saying is getting stronger by the day, even if they cannot translate that into an action or a verbal response.

toddler with hand in mouth resting on their front

At 18 months, parents often choose to move their children to a toddler bed. This can be through choice, their toddler is starting to be more boisterous and climbing out of their cot, or their sleep patterns are poor and there is a perception that this will change in a toddler bed. However, parents should be careful around this transition, especially if it’s to do with trying to do it to improve sleep.

My advice on the move is pretty simple: only do it when it’s a safety necessity, i.e. they are climbing out of their cot and you have no other option. Very rarely do I see a toddler’s sleep improve long-term when they move to a toddler bed. Yes they feel like a big boy or girl, but any improvement is usually short-lived and the causes of the poor sleep patterns usually re-surface; except now they can get out of bed when they want to!

Another factor which can feed into the 18 month sleep regression is potty training as some parents like to do it as early as possible. However, potty training (or toilet training) is all about child readiness, and if a child isn’t fully ready, it can have a big impact on them which can lead to sleep regressing.

Finally, the other point I want to explore with the 18 month regression is the dropping from 2 naps to 1 nap. Most toddlers do this full transition before 18 months, but many are still only fully moving to 1 nap around this age (like my 2nd child Rafferty, who only fully transitioned to 1 nap at 19 months after straddling between 2 nap days and 1 nap days for about 2 months).

During any nap transition phase, a child isn’t necessarily ready to only do the lesser amount of naps every day and that can lead to some overtiredness. So, during any transition period, do make it a transition – be led by your toddler as to whether some days they need 2 naps, and other days 1 nap is fine (with maybe a slightly earlier bedtime).


The first step is knowing what can cause a sleep regression. Whilst it’s a challenging time, knowing what may be causing it can really help you be more aware of things that you can do, which I list below:

baby boy with blue eyes and mouth open

Always provide that little more comfort

The books will tell you not to comfort your child for fear of taking away their capability to self-settle. However they are going through a massive change and absolutely need some extra support; just try and find the balance between supporting/comforting them and bringing back unwanted sleep associations such as rocking or holding to sleep.

Hold back before you tend to them

If your baby suddenly wakes upset in the middle of the night, I would encourage you to just give them a few months to whinge and fuss before you tend to them; if you give them a little space, they might settle back off to sleep which is the ideal outcome for them and you.

Try to keep their sleep space consistent

Unless you are content co-sleeping with your little one, I would try to keep your baby or toddler in their cot or bed during a regression. Otherwise, before you know it, they can be in your bed longer than the sleep regression actually lasts.

Consistency, consistency, consistency

Try to remain as consistent as possible with your baby’s routine, especially with their bedtime routine. There’s already so much change happening, so being consistent with the things around sleep which you can control is so important.

Keep your child’s sleep environment the same

Quite simple: if you use white noise, keep using it during the regression. If they sleep in their own room, try to keep it that way. If they sleep with a night light – albeit I don’t recommend it generally – keep it the same. As with the previous strategy, consistency is critical whilst their little bodies and minds are changing.

Look out for those sleep cues

Be extra vigilant with your baby’s sleepy cues and try to get them in their cot when their tired rather than focusing on the time. For example, if they normally have 1 nap, they may need an extra nap (probably just a short one) to help them get through the whole day as they may be very tired.

Ask those around you for help

Sleep regressions are tough. Really tough. So don’t be afraid to ask for help from people who could help you – even if it’s just to give yourself a chance to have a proper shower in the day, or a quick nap to catch-up on lost sleep. Babies not sleeping is so difficult so try to lean one those people who can support you.


It might be that the 4 month regression has blended into the 8 month regression, or you feel like you’re in a constant sleep regression! If your whole family is being impacted, a sleep consultant (me!) can help you. My gentle online sleep courses will support you to make changes that will allow your baby or toddler to fall asleep independently in around 10-14 days with my gentle sleep training method. If you feel like you’d need some more one to one coaching support, find out about my 1:1 sleep programmes.



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