Three Common Causes of the 9 Month Sleep Regression

by Tara Saltzburg

If your baby is anywhere between 8 and 10 months old, you’re likely in the throes of the 9 month sleep regression. Welcome my friend. If you’ve made it this far, you’ve probably experienced at least one of the common sleep regressions that occur prior to 9 months of age. Sleep regressions are tough on both baby and you, but just like previous regressions, this too will pass! The good news is that there are three common causes of this particular regression and once you understand what’s going on with your little one, you’ll be better equipped to handle it.

Article Contents:

What Is A Sleep Regression?

Let’s start with regression: a sleep regression is simply a period of timeusually 2 to 6 weeksin which a baby who has otherwise been sleeping well is now suddenly waking at night, skipping naps, and/or waking early from naps. The most common regression usually occurs at the 3 to 4 month mark as babies are getting used to life outside the womb, although some parents also experience a 6 month regression and in this case, a 9 month sleep regression


Although these sleep relapses often seem out of nowhere for parents, they really aren’t. Regressions almost always coincide with cognitive and physical changes in babies. As you begin to see an increase in your baby’s gross motor skills, social awareness, and language awareness, you’ll often notice a regression—or relapse—in your baby’s sleep cycles. Routine, dependable transitions and consistency are uber important throughout any regression as they help your baby make sense of the world and take the sleep they need. 

If you think your little one might be going through a sleep regression, keep this in mind:

  • The 1st night is a fluke: Everyone has a bad night now and thenbabies, kids and adults alike! It’s not time to stress yet. 
  • The 2nd night is a coincidence: Start looking out for causes of a sleep regression.
  • The 3rd night makes it a pattern: Time to address the cause of the regression to get baby back on track.

Although regressions can be difficult, try not to stress! Developmental milestones go hand in hand with disrupted sleep, but once your baby is familiar with her new skill, she will likely fall back into the habit of good, consistent sleep.

9 Month Baby Sleep: What to Expect

Between the ages of 9 and 12 months, babies typically sleep around 14 hours per day, including two naps (from 1-2 hours each), although children at this age can vary widely in their sleep patterns. Most babies at this age are able to sleep through the night without needing a feeding and when they awake at night, they are able to soothe themselves back to sleep easily (if it were to stay like this, that would be ideal, right?!). Unfortunately, the 9 month sleep regression will likely soil those plans and disrupt your baby’s current sleep cycle. 

About the 9 Month Old Sleep Regression

This particular regression is sometimes referred to the 8 month sleep regression or the 8-10 month sleep regression because it tends to be unpredictable. Most parents begin to notice the 3/4 month sleep regression almost exactly at 3.5 to 4 months and the 6 month sleep regression right around the 6 month mark, but the 9 months sleep regression varies greatly from child to child and can occur at any point between 8 and 10 months of age.

Perhaps one of the most challenging aspects of the 9 month sleep regression is that parents are not prepared for it. We often assume that sleep gets continually better as baby ages—whereas newborns and infants are expected to wake frequently, babies who are approaching their first birthdays are expected to be “sleeping through the night”.  Unfortunately that’s usually not the case, which can leave parents blindsided, frustrated, and exhausted. 


Although it seems counterintuitive, sleep at this 9 month stage is actually worse than it is at 3 months. Research has shown that after a decline in the average number of sleep interruptions from 3 to 6 months, an increase in night waking happens around 9 months of age. Why? Because the developments here are HUGE and this timeframe coincides with significant socio-emotional advances. Whereas infants in the first 6 months of life are experiencing certain milestones that affect sleep—increased awareness, changes in diet, teething, to name a few—babies at 9 months are dealing with increased physical mobility, people and object recognition, and changes in naps, which can make the 9 month sleep regression one of themore difficult ones to manage.

If your 9 month old won’t sleep or if she is exhibiting any of the following symptoms, you’re likely in the throes of the 9 month sleep regression:

  • waking in the middle of the night
  • waking up shortly after being put to bed
  • restless sleep
  • fussiness or crankiness before falling asleep
  • wanting to sleep with mom and dad
  • shorter than usual naps
  • fighting or fussing at naptime
  • hungry after waking
  • Irritability when woken up


Remember: baby sleep patterns don’t stick to an upward trajectory. Sleep is not a constant—it  improves, it regresses, it stays the same. Teething, illness, holidays, changes in the home, a parent going back to work, developmental leaps—all of these things can affect a baby’s sleep and since life will continue to happen, you’re best to just accept it and roll with the punches.

Causes Of the 9 Month Sleep Regression

Remember the good news: there’s always a reason for a regression and understanding the root cause will better help you handle it. In the case of the 9 months sleep regression, the culprit is likely one of three common issues: separation anxiety, a burst in developmental milestones, and / or fewer naps. Here we’ll take a look at each cause along with some helpful survival tips.


#1. Separation Anxiety

The most common cause of the 9 month sleep regression is separation anxiety. Around this time, babies’ social and emotional development is exploding. They may begin to develop a fear of strangers, exhibit clinginess or show an attachment to toys. They also begin to understand object permanence—the idea that objects continue to exist even when they cannot be seen, heard, touched, smelled or sensed in any way. Your baby understands that although you leave the room, you’re probably just in the next room talking to dad or folding laundry. When you walk out, they begin to think “if mom is close, why isn’t she with me?!” and when she wakes at night, she will understand that she is all alone. Cue the blood-curdling scream. 

While it’s common for many parents to start sleep training around this time, it’s NOT recommended. Separation anxiety is a normal part of development and it’s an indication that, in time, your baby will be confident and independent. At this stage, it’s best to provide lots of comfort and reassurance. By doing so, your baby will begin to understand that although you are not in the room, you will always come back. Once this trust is built that’s when the path to independence—sometimes referred to as “self settling” or “self soothing”—really starts to develop.


To determine if your little one is suffering from separation anxiety, try to evaluate during the day. If your baby is playing contently, walk out of the room to see her reaction. If she was happily playing on her own when you were in the room, but cried when you left, she’s likely experiencing separation anxiety.

Separation Anxiety: The Do’s, The Don’ts & Helpful Tips

Remember that separation anxiety is a result of fear. Your baby is scared to be all alone and she knows you are just a few steps away. To alleviate the impact of separation anxiety, your little one needs reassurance that she is safe and you are there to protect her. 

The Do’s
  • Narrate what you are doing during naptime and bedtime routine
  • Once your baby is in the crib, keep the goodbye short, calm, and sweet
  • Alternate which parent does the naptime and bedtime routine
  • Be prepared for the initial “where are you going?!” cry—Keep your response the same as any other crying situation 
  • Always enter the nursery to provide comfort and reassurance when necessary
  • Pick up and coddle, but it’s best to keep the pickups brief
  • It’s okay to rock and sway if your baby is having a hard time calming down
  • Lay her down and rub her back
  • Have her fall asleep in her own bed, even if you are in the room

The Don’ts

  • No “cry it out”—This is one time where comfort and reassurance are extremely important
  • Maintain the routine! This is no time to implement sleep changes
  • It’s okay to provide extra TLC, but avoid laying down with the baby—allowing baby to fall back asleep on her own is imperative in creating good sleep habits
  • Don’t start any new sleep habits that you don't want to do forever—having baby come to your bed may seem like a good idea, but it’s a sleep habit that will be extremely difficult to break


Separation Anxiety: Helpful Tips

  • Practice separation. Leave your child with a caregiver for brief periods then increase to longer periods. Games like “Peek a Boo” and “Hide the Ball” are also a great way to reassure anxious babies by teaching them that even though mommy’s not here, she will always come back.
  • Create a sleep-friendly environment. Maintain a dark, quiet space that's free of any unnecessary distractions like mobiles or toys. Keep the room cool and opt for ultra soft, non-irritating sleepwear.
  • Schedule separations. Babies are more susceptible to separation anxiety when they’re tired or hungry, so practice a little separation after naps or feedings.
  • Develop a “goodbye” ritual. Develop a reassuring ritual—a special wave or a goodbye kiss, but keep it quick and leave without fanfare. Don’t stall or make it a bigger deal than it is.
  • Keep promises. For your child to develop the confidence that they can handle separation, it’s import you return at the time you promised.
  • Keep things consistent and familiar. Keep familiar surroundings when possible and make new surroundings familiar. Have the sitter come to your house. When your child is away from home, encourage them to bring a familiar object. Have a consistent primary caregiver. If you hire a caregiver, try to keep them on the job long term to avoid inconsistency in your child’s life.
  • Minimize scary television. This one might be a little obvious. It’s probably best for babies (and adults) to avoid scary TV or movies before settling in for some peaceful ZZZs.
  • Set limits. Reassurance is key but set limits. Provide lots of extra hugs, kisses, and cuddles, but don’t bend and make exceptions that can lead to bigger issues down the road. 


#2. Burst of Developmental Milestones

Between 8 and 10 months, there is a major surge in babies’ developmental milestones. A major cognitive leap around this time allows babies to begin examining the world in a different, more methodical way. According to The Wonder Weeks, they now begin to recognize that certain objects, sensations, animals, and people belong together in groups or categories and they are developing the ability to discern differences and similarities—for example, a banana looks, feels, and tastes different than spinach, but they are both food. Babies are also beginning to understand that their actions elicit a response from their parents and it’s likely they will test these limits. If your little one wakes up screaming in the middle of the night, it’s likely she’s testing your limits, and your reactions may determine if this becomes a new habit. 

Physical milestones are also abundant during this stage as babies are becoming increasingly mobile. Your little one may be sitting up, crawling, scooting, or pulling up. Some children may even begin to walk around this time! This is exhausting work, but your little one will be eager to try out her new skills constantly, including at naptime and bedtime! 


Developmental Milestones: The Do’s, The Don’ts & Helpful Tips

There’s a lot going on for kiddos around this age—probably more developments than any other stage in the first year. Babies are developing new skills rapidly and they’ll want to test them out. The most important thing it to allow her lots of time to do so—after she masters the skill, she should settle back into a peaceful sleep routine. Here are some other do’s, don’ts, and helpful tips when you’re dealing with this burst of developmental milestones.

The Do’s 

  • Lower the mattress as soon as your baby can sit up—this will prevent your little escape artist from climbing out and hurting herself
  • Keep interactions short and sweet
  • Make sure that all sleep is in the crib—no naps elsewhere! 
  • Pat the bed and show and tell baby what to do
  • Don’t sleep in late to make up for night waking. Adjust bedtime if necessary, but keep a consistent wake up time.

The Don’ts

  • Avoid being too playful when preparing for sleep—encourage sleep at night and play during the day
  • Of course, don’t start bad habits like laying next to baby to get her to sleep—she may begin to expect this!

Developmental Milestones: Helpful Tips

  • Maintain a normal schedule. When babies are experiencing tons of internal changes, it’s best to keep the routine as consistent as possible. Try to keep a naps and bedtimes around the same time each day.
  • Encourage new skills during the day.  There’s so much to do and explore now that your little one is more mobile! Provide LOTS of time and encouragement during the day for her to practice her newfound skills.
  • Create a sleep-friendly environment. Maintain a dark, quiet space that is free of distractions like mobiles and toys. For the best sleep, keep the room cool and opt for soft, non-irritating sleepwear that will allow the skin to breathe. 
  • Allow extra time to wind down. It’s best to just prepare yourself for a longer nighttime routine because it will likely happen anyway. Consider starting your routine 15 to 20 minutes earlier than usual.This will give your little one some extra time to practice her new skills and show off a little!


#3. Fewer Naps

Another major culprit of the 9 month sleep regression is the transition from three naps to two naps. By the 9/10 month mark, many babies have transitioned to two naps per day and this can certainly throw a baby’s sleep into a tailspin. Fewer naps = cranky, irritable babies (and adults!). This can be a major factor that contributes to the 9 month sleep regression. Breathe. This nap transition is tough but maintaining consistency will help.

If you’re wondering whether you should drop the third nap or if you’re questioning your decision to do so, consider the current nap length. Most babies will need that third nap until around 9 months and sometimes closer to 12 months. If your baby is taking long naps—1.5+ hours—then she may be getting sufficient daytime sleep to be done with the 3rd nap. The general rule is: long nappers are ready to drop the 3rd nap earlier and short nappers will likely still need the third nap.

Fewer Naps: The Do’s, The Don’ts & Helpful Tips

The Do’s

  • Maintain a consistent wake up time
  • Lengthen the time to first nap a little each day
  • Lengthen time between the first and second nap
  • Move bedtime earlier one or two days a week while transitioning

The Don’ts

  • If your baby is still having an occasional third nap, don’t let it run into bedtime. Keep it short—a catnap—and don’t let it be closer than 3 ½ hours before bedtime
  • Don’t sleep later in the morning


Few Naps: Helpful Tips

  • Adjust naps as needed. This nap transition is tough, but you will quickly learn what your baby needs. Don't be afraid to make adjustments to naps as you see fit in order to help your baby get through it.
  • Don't quit cold turkey. Allow for the occasional third nap if your baby seems to need it. She may need to have the third nap a couple of times a week throughout this transition.


The 9 month sleep regression is likely the hardest one you’ll deal with as a parent. If you’re wondering when these regressions end, I promise they do, but prepare yourself: another regression may happen around 12 months and/or 18 months and just when you think you’ve got sleep figured out, you might be surprised when a 2 year sleep regression creeps up (I’m sorry). 


Babies are reaching so many new physical and cognitive milestones between 8 and 10 months. The good news is that the cause of this particular regression is likely one of three major culprits: separation anxiety, a burst in developmental milestones, and/or fewer naps. Give lots of TLC to ease separation anxiety and allow tons of time during the day for practicing new skills. The most important thing you can do during this transition is to be patient. This regression will not last forever and once your baby masters her new skills, she should fall back into a good sleep routine. And hopefully you will, too.

Good luck!

XO, Tara

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Tara Saltzburg

About The Author

Tara Saltzburg founded Westyn Baby when her son was an infant battling severe eczema. She was always on the lookout for products that would minimize the irritation and ease his discomfort, but safe, non-irritating pajamas proved difficult to find. Tara started Westyn Baby in 2016 with a mission to create better, safer sleepwear for kids - sleepwear that's exceptionally soft, flame-retardant free, sensitivity-friendly, and durable. Read more about WB sleepwear.

Tara was born and raised at the NJ shore and attended Penn State University, where she played soccer and discovered her love of mountain life. She is a mom of one boy and hopes to eventually have enough kids to form some sort of athletic team. She and her family currently reside in Central Pennsylvania and spend the summers in Stone Harbor, NJ.