The Toddler (18-ish) Month Regression: What is it and What can be Done About it?

When does a baby become a toddler? Everyone has a different definition of this milestone. For many parenting experts “toddler” is the term used after 12 months or after a baby starts walking. When it comes to sleep, the graduation from “baby” sleep to “toddler” sleep usually happens around 18 months. This transition involves a subtle biological change associated with the transition to one nap, but the sleep regression that many toddlers experience is caused by an explosion of cognitive and emotional development. We call this the 18-ish month sleep regression, because it can happen anywhere between 15-24 months. For most toddlers it hits right around the 18 month mark. Your toddler might have a true regression and get better with minimal effort after a rough week or two OR she might get stuck in a bad pattern that will only get better with intervention. The key to getting back on track quickly depends on how you interact with your child during what can be a tricky time.

The Science: Right around the 18 month mark toddlers go through an explosion in development. The transition to one nap has usually happened by this time (see our nap blogs here) and making it through the day on just one nap can be a tough transition. In addition, recent research has shown that the biological bedtime conferred by the circadian rhythm drifts by as much as an hour later during toddlerhood. (In other words, that same tried and true baby bedtime you’ve had for months stops working!) This circadian rhythm shift is problematic, because the strongest drive to be awake happens right before the biological bedtime. The practical consequence of this is that you can end up with a toddler, who is obviously tired from having just one nap, but who cannot sleep at bedtime (more on that here).

It gets worse. Now, biologically you have a tired child who cannot sleep, so what’s an overtired toddler to do with all that extra time? Unfortunately, this age is also when testing behavior happens and it’s also a time when a second separation anxiety can hit with a fury (see our blog on the first separation anxiety regression at 9 months here). Some children will fill their extra awake time with experimentation that many parents interpret as active manipulation, but it’s really more just figuring out limits and consequences – What happens if I yell? Can I get out of this crib? Jumping is fun! How long can I jump? What happens when I sign/ask for milk? What happens when I sign/ask for a snack? What happens when I sign/ask for the stroller? Is it nice to sleep on the floor? Can I sleep in my parents’ bed?

On the other hand, with moderate to severe separation anxiety some children develop genuine, but sometimes irrational, fears – Where is my mom going? What if she doesn’t come back? What if I need her and she doesn’t come? What is that shadow? A dog barked at me today and it was scary. What if a dog comes in my room?

Since natural wakings happen throughout the night at the end of every sleep cycle, these problems can repeat themselves for hours in the middle of the night. This can be even more challenging for children who have not yet developed strong language skills (most haven’t at this age), because it’s hard to know whether cries should be interpreted as “I want that toy” or “I’m worried”.

Some children can experience elements of both of these issues, making it even more difficult to figure out how to respond appropriately.

What do I do about this regression?

Avoid making big sleep changes during this time. Sometimes you can’t avoid life changes, like moving or the arrival of a sibling, but if your child has sleep issues or if you want to make a change in your child’s sleep experience, then it’s best to try to make those changes before the 18 month mark or wait until this volatile period is over (e.g. sleep location transitions, pacifier weaning etc). We know that sometimes you just can’t wait, but for those situations we recommend considering booking a consultation with us, so that we can evaluate your child’s individual needs.

Provide your child with consistency and clear limits. If your bedtime routine changes every day or doesn’t have a defined end, then it will be tough to convince your child that there is a reason to stop reading books, singing songs or otherwise engaging with you. Intermittent “giving in” is actually very reinforcing (think gambling), so negotiating with your child (a la if I read you one more book, then you have to promise to go to bed) can actually backfire in the long run. It can be really helpful to use a bedtime checklist with pictures, or to glue pictures of the steps in your routine on cards that your child can put in an envelope when each step is complete. Once the end of the routine happens, you should not give in with more books, snacks or activities. The end should be the end. This doesn’t mean that your routine cannot involve you being in the room with your child, but even if you stay in the room, you can and should expect that your child follows the “sleep rules” at the end of the routine.

Respect your child’s need to participate. At this transition toddlers generally want to play an active role in their experiences. Although you should maintain a consistent bedtime routine, you should incorporate “jobs” and limited choices for your child to actively participate in the process. For example, you can offer two pair of pajamas and let your child choose one, you can ask your child to get his toothbrush out of the cabinet or move the stool to the sink, or you can have your child find his lovey and put it in his crib. All of these things give your child some of the control that he’s craving, while still allowing you to maintain predictability and limits. Because let’s face it, limits are actually reassuring to your child who wants to know you are able to handle any situation – including bedtime!

Determine your child’s biological bedtime. Make sure you are asking your child to sleep when he’s ready to sleep. Remember, the biological bedtime can drift as much as an hour later during toddlerhood. If your child is not ready for sleep, then your intervention will not work no matter what strategy you use. Don’t put your child down until it’s clear that he’s able to sleep. The best way to figure out your child’s bedtime is to take his average fall asleep time from the last week and put him down at that time. This might be a socially crazy time, like 10:00 PM, but if that’s when your child normally falls asleep, it’s the right place to start. Once your child is falling asleep quickly after your routine, you can gradually move bedtime earlier by 20 minutes a day. Once you reach the time that works for your family stick to it and try not to vary bedtime by more than 30 minutes from night to night.

If your child is a tester….

It is extremely important that your routine have a defined end and that you reinforce that after the routine is over, it’s over. You should change your behavior after the bedtime routine. During the routine, you engage, you snuggle, you make sure all of your child’s needs are met. After the routine ends, you should transition to night-mode: calm, soothing murmurs or just soft “shhhh”ing, and no more conversation, toys or games.

If your child is in a crib (which we strongly recommend), then you can sit outside his door or frequently check in while repeating a good night phrase such as “good night, I love you, it is time to sleep.” Don’t engage or start a conversation. Repeat the phrase when you go in or in response to requests. Do the same thing in the middle of the night if your child wakes and makes requests.

If your child is in a bed (we don’t recommend making this transition before age three), then you may have to walk your child back to bed over and over. Every time he gets out, take his hand and put him back in bed while repeating your good night phrase. Repeat this in the middle of the night if he gets out of bed.

For more information on toddlers and crib climbing, read our blog here.

If your child is anxious….

Figure out what is causing the anxiety. At this age it is totally normal for a toddler to become concerned that you might not be available when you leave or in the middle of the night. From an adult perspective we know that this is an irrational fear, but from your child’s perspective it is very real. Your child is learning how to regulate emotion and identify which situations deserve an anxiety response and which don’t. If this is the cause of your child’s anxiety, then you will want to make sure that your child gets to see you at least once during nighttime interactions in order to alleviate that anxiety.

For some toddlers an event can trigger anxiety. We’ve worked with children who have had bee stings, car accidents, fire alarms, and major illness.  Even more mundane stimuli, like a dog barking unexpectedly or a thunder storm can trigger night anxiety. If an identifiable stimulus is the source of your child’s stress, then you will need to be supportive and reassuring during the night until the stress from the event passes. This may mean sleeping in your child’s room for a time or staying with your child until he is asleep.

When trying to figure this out, don’t project your emotions on your child or ask leading questions like “Are you scared of the dark?” or “Did you have a bad dream?” or start checking under beds. That’s the fastest way to give your child new anxieties! If your child’s anxiety seems to be more than just minor and passing, please see your child’s doctor for further evaluation.

It’s also important to note that sometimes toddler sleep problems can start as anxiety, but can evolve into testing. Imagine a scenario where your child has a bad dream and wakes terrified in the middle of the night. Obviously, you would respond with comfort and support to help him get through that tough night, BUT there is a good chance that your child might like the extra comfort that you offer and then in the future, he might wake up and call for you and use the words “bad dream,” because a bad dream led to a really nice outcome before. You can usually tell if this is happening, because the tone of your child’s waking will typically be different even when the language is the same.

If you catch this sleep regression right away and if you have your child’s biological bedtime correct, then it should only be a few nights of drama before your child is back on track. If your child has been off course for a while and you aren’t sure where to start, then consider booking a consultation with us to help you put together a plan.

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Need personalized support? Book a consultation with us.

© 2014 Baby Sleep Science: Sleep Resource Center



  1. lorrishawn says:

    Is the shift in bedtime at this stage associated with a shorter night? My little one is just over 18 months and in the past month as shifted her fall-asleep time from 7:30 to 8pm, but is consistently sleeping until 6:30 or 6:45 (sometimes 7am!), whereas she was previously waking between 6 and 6:30. I did try waking her regularly before 6:30 in an attempt to shift the bedtime backwards, but it only worked for a couple of days.

    My concern is that if I keep letting her “sleep in” it is going to pull her bedtime later and later. Should I be waking her to keep bedtime at 8, or has she just kept her night length and shifted by 30 minutes?

  2. Mel says:

    Thanks for the tips. … mostly just good to know this is part of a normal sleep regression. My 18 month old who was sleeping well has now started to wake in the night and can take hours of crying to get back to sleep. After 3 weeks of this (me getting a maximum of 3 hours sleep a night) I’m really struggling. Especially as I’ve got a busy 4 year old that doesn’t daytime nap, so I never get a chance to nap with the 18 month old.
    We have gone back to sleep training methods that worked for us at an early stage. As the sleep regression started with my little one being sick we were slow to start the real sleep training. … but fingers crossed we get results soon as I really don’t know how you cope much longer.

  3. saragoodrich says:

    I am really grateful for this article. My almost 21 month old has been crying at bedtime, hysterically, for a week now. And last night she woke up three times, an hour apart each. Usually a quick pat on the back does the trick but last night she only wanted to be held. We’re exhausted and confused. I never knew about the biological bedtime issue and wondering if her 6:30 bedtime that’s worked like a charm for 6 months is now too early, but my question/concern is, she is SO whinny starting usually around 5:00 that we think she’s behaving this way out of tiredness, hence putting her to bed at 6:30. I will experiment with pushing her bedtime back an hour, since a she’s been crying for an hour anyhow, but I do fear and extra hour of whinning, fits, etc. She’s never been a great sleeper but never to this extent… Thank you for sharing your expertise with us!

  4. Maureen McMahon says:

    My 12.5mo, who usually wakes up around 7:15am, has woken up a couple of times at 5:15/5:30am recently and won’t fall back to sleep. My husband and I think perhaps he was startled awake by a bad dream, as he jumps up and starts crying. There is nothing obviously wrong otherwise. (He’s been walking for 1.5 weeks and has been taking one nap for a couple of weeks as well.) I’d love to see a dream post from you: when do dreams start? Any recommendations for pre-verbal toddlers?

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