Once You Sleep Train, Will You Ever Need to Re-Sleep Train?

consistency developmental milestones sleep regressions sleep training Sep 09, 2022
Once You Sleep Train, Will You Ever Need to Re-Sleep Train?

Parents of sleep-trained babies (or parents considering sleep training their baby) often ask me if they will need to re-train their baby at a later date if they’ve already been sleep trained. There are a lot of components that can go into this scenario, but my answer is generally, no. 

There are times that babies’ and toddlers’ sleep can (and will!) get thrown off. But, developing the skills to sleep well and independently isn’t a short-term phase. Babies who know how to fall asleep independently and sleep well will remember how to do so.

The key here is how we as parents respond when those bumps in the road pop up out of nowhere, especially when sleep has been going well previously!​​

Common Reasons That Can Cause Disruption to Your Baby’s Sleep

Even if your baby sleeps well and is able to fall asleep independently, there are times when your little one may experience some disrupted sleep. Things like environmental changes, developmental shifts, and regressions due to illness can all throw a wrench in your baby’s sleep.

The good news though, is that knowing how to fall asleep on your own is not a skill that you forget! These changes that may be causing shifts in your baby’s good sleep habits are temporary, and if approached in a particular way, will pass quickly and your baby will go back to sleeping well again. 

The following issues are the most common reasons to look for when determining what may be causing a disruption in your baby’s sleep:​​​​​​​​

Change in schedule.

If your little one has recently begun fighting naps or bedtime, it may be time to drop a nap! 

Here are a few reasons why you might want to consider dropping a nap:

  • Your baby is suddenly up at 4 or 5 am every morning and won’t fall back to sleep.
  • Your baby takes 30 minutes (or more) to fall asleep.
  • Your baby keeps waking in the night, sometimes for hours, and is usually not upset. They simply just can’t fall back to sleep!
  • Your baby’s last nap of the day keeps shifting bedtime later by more than 30-60 minutes.
  • Your baby is suddenly taking 30-minute catnaps when normally they sleep for at least an hour.

If you do think your baby is ready to drop a nap, changes to your baby’s everyday routine can be tough. It can be difficult figuring out your baby’s new wake windows and nap times, and dropping a nap can even cause overtiredness, night wakings, and early mornings at first. 

If this transition doesn’t go as smoothly as you hoped, remember that it won’t stay this way forever. Stay consistent! Your baby will get used to his or her new schedule and wake windows and should go back to sleeping well fairly quickly. It’s when we drastically alter our behavior and reactions that these disruptions can linger longer (i.e. we suddenly begin bringing baby into our bed every early morning waking for a week…and baby continues waking because they’re enjoying this newfound activity!). I am a mom - I totally get it. We love those early morning cuddles as much as they do! Just remember, the more consistent we are with something, the more of the “new norm” it can become. So, I recommend keeping things like that more random so that baby doesn’t think it’s how mornings go now (or whatever behavior it is that has become the new norm). 

Change in environment.

We often forget that life changes and stress can greatly impact our sleep. Our children are no different! If your baby who is typically a good sleeper begins to need a little extra help falling asleep, consider any new things going on in their life. 

A new baby in the home, moving to a new house, beginning daycare, potty training, or transitioning into a big kid bed can all temporarily affect sleep. It’s our consistency around sleep that will have a long-term effect.

New physical skills.

The most common physical developmental milestones that can affect sleep are:

  • Rolling
  • Sitting up
  • Crawling
  • Standing 
  • Walking

When babies are going through a change or learning a new skill, they will typically wake in the night to practice their new skill because it is so new and exciting! When they haven’t mastered these new skills though, it’s not uncommon for them to accidentally get “stuck” standing or rolling and need your help. Set aside extra time during the day to practice (rolling, sitting back down from standing, etc.) with them, so that nighttime can stay dedicated to sleep.

Developmental milestones.

Just as physical milestones can disrupt sleep, so can cognitive goals! The most common cognitive developmental milestones that can affect sleep:

  • Changes in sleep cycles (“4-month sleep regression”) [1]
  • Increased awareness
  • Separation anxiety
  • Language bursts 
  • Fears

Your baby is becoming increasingly more aware during these milestones, which can keep them awake noticing shadows and sounds. More sleep cycles mean your baby is spending more time in light sleep, which means a dog bark or loud noise is more likely to wake them! Even language bursts are just plain old fun to your baby and they may want to practice babbling throughout the night. It’s up to you as a parent to decide whether your little one needs your assistance during these wake-ups, or can fall back to sleep on their own (which they’re likely able to if they’re already sleep trained!). Or, if they do need help or comfort for some of these cognitive shifts, keep an eye on your reactions, consistency, and demeanor in order to help these disruptions pass quickly.


When babies are sick they’re so uncomfortable and don’t sleep well! Their need for sleep and comfort comes first; it’s always helpful to give extra cuddles, comfort, and reassurance during this time. But again, keep an eye on your consistency around sleep and what you introduce during these times. 


Circumstances, environments, and routines can be a tough adjustment for little ones when we travel, and it’s normal for good sleep habits to be thrown off. The good news is that this is usually a temporary disturbance and your baby should return to sleeping well once they return to their usual sleep environment and routine!

Remaining Consistent During Your Baby’s Sleep Changes

If your baby has learned how to fall asleep independently, your baby’s sleep will go back to normal on its own, as long as new or old sleep associations are not consistently introduced during these phases.  

Oftentimes, parents will try to “fix” these sleep disturbances by introducing new or old sleep associations. While this may work temporarily, you may be left with your child developing a new sleep habit that they may not have originally needed. ​​​​​​​​

If you stay consistent through these changes, meaning add comfort as necessary or transition down on the number of naps when appropriate; BUT still encourage your baby to sleep without the introduction of new or old props, your baby will get back on track pretty seamlessly.

Some situations require more comfort, checking in, contact, and care, but your child will not unlearn how to fall asleep on their own once they have that skill. So, remind yourself of that when needed! 

If ​​​​​​​​staying consistent during a milestone, illness, or another sleep disturbance wasn't possible and things seem to be totally off track, that’s okay! You might need to implement a sleep training 'refresher', but after a few nights, your baby will be sleeping well again​​​​​​​​.

If you find yourself still struggling with your little one’s sleep, please know that you are not alone and that I am here to help. Download one of my comprehensive sleep guides for step-by-step guidance on helping your little one learn to sleep independently. 


[1] https://www.ncbi.nlm.nih.gov/books/NBK19956/

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