The 12-15 Month Sleep Regression

Nov 2, 2021
4 min read

By this point you are a pro at handling sleep regressions, so we know you’ve got this, but just in case you want an extra helping hand, we’ve put together some more information about regressions to help you along the way....

How long should a 15 month old be sleeping?

At 15-months, we recommend your baby has one long midday nap of about 2hrs - 2hrs 15 minutes between the hours of 12:00 and 2:00 PM. Napping at this time means they are more likely to fall asleep, stay asleep (all things going well) and it is when sleep will be the most restorative.

What is a sleep regression? 

A sleep regression is a period when a baby or toddler who has been sleeping well suddenly starts waking at night, being difficult to settle and/or skipping naps. To learn more about when and why this can happen in general, read our full article on sleep regression.

What is the 12-15 month sleep regression?

A sleep regression is a period when a baby or toddler who has been sleeping well suddenly starts waking at night, becomes difficult to settle and/or is skipping naps. The 12 - 15 month sleep regression is all based around nap transitions. Your little one’s sleep will seem to regress simply because they’ve outgrown their former sleeping pattern.

So, you’ve come through the pesky 4-month sleep regression, then tackled the 8-10 month regression and are now being faced with yet another one?


We know it sucks, but this regression is different to the regressions you’ve experienced so far. It’s unlike the 4-month regression as it’s not neurological and it’s not like the 8-month regression as it’s not physiological. This one is all based around nap transitions. Your little one’s sleep will seem to regress simply because they’ve outgrown their former sleeping pattern. 

What is a nap transition? 

Dropping a nap is no easy feat, this transition happens over time. Babies need to decrease their amount of naps incrementally, but that won’t happen on its own as babies and toddlers still need your guidance to help ease these changes. A way of helping your wee one is by implementing a nap routine - this will help you to know when the transitions happen and how to handle them.

At around 12 months your baby might refuse to take 2 naps and a lot of parents assume this means it’s time to transition from 2 naps to 1. For some babies, this could be the case, but for others, it can be closer to the 15-month mark. If your baby is alert or a really good sleeper who sleeps past 7 AM, you may find that they’re able to drop to one nap shortly after 12 months, but if your little one is waking earlier in the morning then it will be closer to 15 months. 

TIP: Don’t rush this transition, you’re wee one will be adjusting to this new change and may start waking up earlier in the morning or after one sleep cycle at bedtime for a few days. Just like the 8-month regression, this will resolve itself once your baby is comfortably through the nap transition period. 

To find out more about how and when your baby will drop their naps, read our article here. 

Signs of the 12-15 month regression 

The main sign that your little one is going through a regression is that their sleeping pattern takes a turn for the worse, but some other signs to look out for are: 

  • Waking in the night and staying awake for ages 
  • Fussiness
  • They can’t resettle if they were previously able to
  • Refusing to nap
  • Crying when settling for a nap or at bedtime

What causes the 12-15 month regression?

As we mentioned in our sleep regression article, nothing as such causes a regression as they are developmental phases that all babies go through. However,  unlike the previous 2 regressions, the 12-15 month regression is mainly caused by the nap transition that happens at this age. 

But there are also other certain things that happen alongside the regression that could affect your little one’s sleep like:

  • Growth spurts and teething.
  • Separation anxiety. 

Around the 16 month mark, you may find that your wee one will start to experience separation anxiety. As your baby gets older, you may find that they become clingier and may even cry when they are left with someone other than you and that’s because babies at this age start being able to tell one adult from another and they start to develop the concept of object permanence.

Object Permanence is the understanding that objects continue to exist even when they cannot be perceived (seen, heard, touched, smelled or sensed in any way.) In the earlier months of your baby’s life, you may have noticed that your wee one liked to play peek-a-boo, because in their minds once you had disappeared from their line of sight, you vanished and then you re-appeared again (best trick in the book), but for older babies this is no longer the case.

How to combat separation anxiety?

  • Let your child know when you are leaving and coming back
  • Make time for extra snuggles and one on one play at the end of the day
  • Leave their room with a smile on your face. Try to stay positive so your anxiety doesn’t rub off on them.

How long does the 12-15 month regression last?

Thankfully this regression is not permanent like the 4-month regression and will eventually go away once your little one has got used to their nap transition. Nap transitions can last a couple of months on and off. 

Each transition is different and it purely depends on your little one’s nap structure leading up to the transition, which is made a lot easier if following our Sleep Programs

Do sleep regressions ‘ruin’ the sleep training you have done/doing/plan to do? 

No, in fact having a routine to follow and being more prepared will help you through the regression - by implementing good sleep habits early on.

Our Sleep Programs helps to regulate your little one’s sleeping patterns and helps your baby adjust to big changes like regressions and nap transitions. 

How to deal with the 12-15 month regression? 

  • Remember this is just a short phase and it will be over in about 6 weeks, so stick to your routine and be careful not to start creating more dependent sleep habits/ sleep associations that will be harder to shake off later.
  • Make sure your routine (naps & awake times) are age-appropriate. 
  • Foster good sleep habits/sleep environment such as: - Dark room & White noise
  • Having a bedtime routine to follow. Check out our tips for creating a good bedtime routine and why it’s important here.

Remember that this isn’t like the other sleep regressions that you would have experienced, it’s all based around your little ones nap transitions. Nap transitions are certainly not easy, after all, no one likes it when their little one goes on nap strike, but you can manage this sleep regression and nap transition better by following our Sleep Program.


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