How Long Does the 4 Month Sleep Regression Last? And, How to Shorten It

How Long Does the 4-Month Sleep Regression Last?The 4-month sleep regression is an exhausting time in a family’s life. Your baby might be waking every 1-2 hours all night and taking short naps. And, if your baby is going through this, you’re probably asking yourself how long the 4-month sleep regression lasts. Based on my 10+ years as a sleep consultant, it doesn’t have to be as long as you think. In this blog post, I’ll share tips to get through the 4-month sleep regression.

What Is the 4-Month Sleep Regression?

The 4-month sleep regression marks the time when your baby stops sleeping like a newborn and starts sleeping more like an adult. Newborns spend a lot of time in deep sleep which is why they can sleep through so much in those early days. Once they go through this period of development, they change their sleep cycles which means they are sometimes only in light sleep and will wake more easily. So, the 4-month sleep regression is only the name we give this period of development. Do all babies go through the 4-month sleep regression? Yes, all babies go through this change and there isn’t a way to stop it. It’s actually a good sign your baby is developing appropriately!

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The most common signs of the 4-month sleep regression usually include one or more of the following:

  • Waking a lot at night (even when they used to sleep in long stretches) – waking every 1-2 hours at night is common.
  • Taking short naps of 20-30 minutes, sometimes 45 minutes.
  • Can’t be put down awake (or even asleep sometimes!) Baby wants to sleep only in your arms or a carrier/sling.
  • Irritability and Fussiness (though that can be simply due to sleep deprivation!)
  • Needing to be put back to sleep the same way each time (e.g. rocking or feeding back to sleep).

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How Long Does 4 Month Sleep Regression Last?

The 4-month sleep regression starts around 3 to 4 months old and lasts around 3-4 weeks at its peak. But since it’s a permanent change to how your baby sleeps, it doesn’t ever “end” in a traditional sense. Some babies will begin (or go back) sleeping fine again. But, others will continue to wake up frequently at night and take short naps. Over the past 10+ years, I’ve gotten phone calls or e-mails from parents of 4-month olds, 6-month olds, 10-month olds, 12-month olds, or 18-month olds with virtually the same exact sleep problems: frequent night-waking and/or short naps.

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How to Shorten This Regression

The only way to “end” the sleep problems this regression causes is to help your baby sleep better with their new sleep cycles. If you don’t want this regression to last months when it can last just a few weeks, you need to help your baby learn to put sleep cycles together.

Linking sleep cycles sounds simple enough when you’re an adult but for babies, it can be difficult. The most common reasons babies struggle moving into the next sleep cycle is due to hunger and sleep associations. A sleep association is a way in which your baby falls asleep. Because this is how they fall asleep, this is how they expect to fall BACK to sleep. Examples of sleep associations include rocking, feeding, bouncing, sucking on a pacifier, and driving in a car.

So, the key to shortening the 4-month sleep regression is simply to have your baby fall asleep the same way they will need to put themselves back to sleep. We typically do this by teaching babies to self-soothe with gentle sleep training. There are many methods to do sleep training or sleep coaching. The key is to find the one that works best for your baby’s temperament and personality. Please poke around and read through our many blog posts about this topic and more!

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Baby Insomnia or Split Night: Why It Happens and How to Fix

Baby insomnia is when your baby is awake in the middle of the night for 2-3 hours at a time. It is sometimes called a “split night” and usually lasts for weeks or months. This post will explain why baby insomnia happens and ways you can fix the problem based on my 10+ years as a sleep consultant.

What Is Baby Insomnia or a Split Night?

Insomnia is usually defined as the inability to sleep when you are actively trying to sleep. This could mean that it’s hard to fall asleep, hard to stay asleep, awake for long periods at night, or wake up too early in the morning.

Baby insomnia is the same but sometimes occurs when there is a mismatch between how much sleep a parent thinks their baby needs and how much sleep their baby actually needs.

When a parent comes to us with a case of baby insomnia, it usually means the baby is awake for long periods in the middle of the night (2+ hours) and can’t go back to sleep. When a baby is taking too long to fall asleep at night or waking up too early, we don’t typically call that “insomnia.” Same for a toddler stalling.

In most cases, if your baby is awake at night but happy and not crying, this is a good indication they have insomnia.

If your baby is crying when they are alone but awake and happy when you’re holding them, that can also be insomnia for a social child. After all, tossing and turning alone isn’t fun for anyone when you can’t sleep!

This is often called a “split night” because your baby might sleep a long stretch at the beginning of the night, wake up for 1-3 hours, then finish their nighttime sleep. They are “splitting” the night into two long fragments.

What About When Baby Falls Asleep In Your Arms But Wakes Up When Put Down?

If your baby is falling asleep in your arms but waking up when you put them in their crib, we would NOT consider that insomnia. If your baby will only sleep in your arms or on your chest, this is usually a case of sleep associations not insomnia.

Why Is Insomnia Bad?

The reason this is an issue is it’s not as restorative for your baby’s sleep, in general, and can cause problems with their schedule. It can also cause your child not to get enough sleep in a 24-hour period. And, just like adults, they can feel tired during the day.

So, why does insomnia happen in babies?

Top 5 Reasons for Baby Insomnia

There are 5 primary reasons for long night-waking in children:

  • Developmental Milestones and Sleep Regressions – The most notable reason your baby might wake up for long periods at night is that they are working on a new skill or developmental milestone. When our minds are very busy, we have trouble sleeping (obviously). For adults, it’s often due to something about which we’re stressed or worried. For babies, it might be a new skill they’re learning. During some developmental periods, you’ll also notice a sleep regression, a period of time when your baby starts waking a lot for no apparent reason.
  • Scheduling Problems – Besides developmental leaps, a scheduling problem is the most common reason for insomnia. But, it can be complicated how to fix it which I will explain below.
  • Medication Side Effects – Although it’s rarer, there are occasionally children on medications that have a side effect of insomnia.
  • Allergies and Milk Intolerance – In a small number of cases, milk intolerance is to blame for sleeplessness and other allergies.
  • Sensory Processing Disorder – Sensory Processing Disorder (SPD) can also cause insomnia in babies and toddlers. This was the case for one of my clients with a 2-year-old at the time. He would wake up for 1 to 3 hours every single night. In the end, a weighted blanket was the only thing that helped. SPD makes it difficult for children to process information from their senses and then respond appropriately. Typically, one or more senses over- or under-react so it isn’t difficult to see how that could impact sleep.

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What About Teething and Illness?

Teething and illness can both cause discomfort and thus, sleeplessness. However, this is typically short-lived. And, by the time you are wondering if your baby has insomnia, it’s usually over. Therefore, I didn’t include them in the list. Babies get teeth on and off for 2+ years. If they have night-waking related to teething, it’s usually when the tooth is cutting through the gums and then it’s over. That typically takes 3-5 days per tooth. In some cases, they might get two at the same time or back-to-back but even then, it will typically last two weeks or less of sleeplessness (with some nights being better than others.) Insomnia typically lasts several weeks or months.

Ways to Fix Your Baby’s Insomnia

For the purposes of this article, we will be sharing how to fix insomnia when it’s a scheduling problem. For any potential medical or development issues, please see your medical provider.

If your baby has had insomnia for weeks or months, you probably want to fix it. I say “probably” because in some cases, a split night isn’t the worst thing in the world. If your baby is happy and thriving, it may be a phase they go through until they are ready for their next schedule, for example. If it’s keeping you up at night, consider changing your own sleep environment to combat it rather than changing theirs.

However, if your baby seems exhausted during the day and/or is not thriving, you should definitely address the issue. But, how do you fix insomnia?

If it’s due to a sleep regression, you typically need to ride it out. Although there are sleep regressions at various ages, we find that insomnia occurs most during the 8 to 10-month sleep regression and during the 18-month sleep regression in our experience. During other sleep regressions, we notice frequent night-waking but not necessarily long periods of non-sleeping.

When insomnia is due to a scheduling problem, thankfully, there are things you can do to fix it! Unfortunately, it can be one of the most challenging sleep problems to fix. Here are a few tips:

  • Too Much Daytime Sleep – This is probably the easiest scheduling problem to solve. If your baby is older than 6 months old and napping longer than 2 1/2 to 3 hours during the day, we typically need to reduce the amount of daytime sleep. Note: You don’t have to reduce it if there isn’t insomnia. This is only if it’s causing an issue at night. When your baby is sleeping too much during the day, they might not be sleepy enough at night to stay asleep. They might fall asleep fine at bedtime (or not), but they simply can’t stay asleep.
  • Bedtime Is Too Early – You might know about wake windows so you put the baby to bed at night after their appropriate wake window. Great! Only sometimes this can cause split nights. For example, your baby naps from 2 to 3 PM and can stay awake 3 hours. So, you put them to bed at 6:00 PM. Unfortunately, this can cause split nights because while early bedtimes are good, your baby’s internal clock might be set for “nighttime sleep” from 7:00 PM to 7:00 AM, for example. If their bedtime is too early, they treat bedtime more like a long nap than bedtime. This happens to adults, too. We see this to happen to babies most when they are transitioning from two naps to one nap
  • Too Long In Bed Problem – Similar to bedtime being too early, another issue is what Dr. Ferber calls the “Too Long In Bed Problem.” Essentially, you have your baby in bed for more hours than they are capable of sleeping. If this is the case, you need to try to have your baby in bed for just the right amount of hours. The worst thing you can do in a case like this is let your baby “sleep in!” The amount of sleep in a 24-hour period will stay relatively constant. If your baby needs 13 hours of sleep a day, naps for 3 hours, and is in bed for 12 hours, they will likely be awake for two hours in that 12-hour period whether it’s at the beginning, the end (early waking), or in the middle (split nights.) To fix this issue, “squeeze” the sleep together by setting an appropriate schedule with only the number of hours of sleep your baby needs.
  • Overtiredness – Overtiredness can be terrible for your baby’s sleep but usually, it causes frequent night-waking, not insomnia. In some cases, though, it can cause insomnia. Our bodies release hormones (cortisol) to fight fatigue and give us a “second wind.” If we go to bed overtired, we might wake up restless and unable to sleep. In my experience, babies who have insomnia due to this reason are fussier at night than for the above reasons. They are quite miserably tired.


As I mentioned, insomnia is one of the most challenging sleep problems we face as parents and as sleep consultants. Although it should feel simple to put your baby to sleep when they’re tired, there is a bit of an art form to it. When we work directly with families, we typically keep a sleep log while fine-tuning the schedule so we can accurately see the primary cause of insomnia. If you try to solve the wrong problem, you can make sleep even worse! Give a few things a try for 2-3 days and then make more adjustments. If you get stuck, feel free to reach out to us!

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Solve Your Child’s Sleep Problems by Dr. Richard Ferber

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When to Move Baby to a Crib and 5 Tips How to Transition

When to Move a Baby to a CribWhen to move baby to a crib is 6 months old, on average. However, there are several factors to consider when deciding when to transition baby to a crib. This post will discuss these factors so you can decide the best time to move your baby to the crib and do it successfully. Let’s get to it!

Weight Limits of Bassinets

How long your baby sleeps in a bassinet will include a few factors, one of the biggest ones being their weight. Most bassinets have a weight limit that ranges from 15 to 35 pounds. Be sure to check your specific bassinet’s weight limit.

For example, the Arms Reach Bassinets all have an age recommendation of 5 months or when your child begins to push up on their hands and knees. Other bassinets have a suggested age and weight limit. For example, The CRZDEAL Bassinet suggests up to 6 months and no more than 30 pounds. Smaller bassinets often have a weight limit of 15-25 pounds, though. So you will want to be careful to check your specific bassinet’s limitations. Be sure to stop using a bassinet when your baby is too heavy for it.

Sharing a Room

Another thing to consider when deciding when to transition your baby to a crib is whether you plan to continue sharing a room. If your baby’s crib is too large to fit in your room, then moving them to a crib might also mean moving them to a room that’s separate from you. That’s a big step!

The AAP recommends sharing a room but not a sleep space “for at least 6 months but preferably a year.” Therefore, if your baby is not yet 6+ months and the crib is in another room from yours, you should consider keeping the baby in the room with you for a bit longer…as long as it’s safe to do so. If your baby is already 6+ months old then they may be ready to sleep in their own room.

Babies are loud sleepers, so if your baby is keeping you awake at night but doesn’t need your attention, consider wearing earplugs. With earplugs, you will still hear your baby crying but not be woken up with every noise.

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Growth and Developmental Milestones

Even if your baby isn’t necessarily outgrowing the bassinet due to their weight, they might outgrow it developmentally. Some babies become mobile at a faster rate than other babies. That means they might be rolling over or pushing up on their hands and knees. One of my clients had a baby who started crawling at 6 months old. That’s very young!

(Note: If your baby isn’t mobile, try not to worry! My sons took a long time to crawl and now they are both teen athletes!)

So, when you’re considering when to move baby to a crib, consider that it can be unsafe if they can sit up in a bassinet or crawl off the side of a bed.

Comfort of the Bassinet

Keep in mind that some babies simply don’t like bassinets. My second son was one of them. No matter what I did, he wouldn’t sleep in it for even 5 minutes. I tried warming the surface and putting him all the way to sleep, etc. but he would simply NOT sleep there! He seemed to sleep in his crib just fine, though. To this day, I still can’t tell you what he didn’t like about the bassinet. Perhaps it was the thinner mattress or how small it was. It’s hard to say but if your baby doesn’t seem to like it, maybe it’s just the bassinet! Therefore, your baby won’t sleep in the bassinet long. Most babies, however, sleep in a bassinet until 4 to 6 months old and then start sleeping in a crib.

The Bottom Line: When Should You Move Baby to a Crib?

The bottom line is you should move your baby to a crib when it’s unsafe to keep them in their current sleep space. You might want to move your baby for other reasons and that’s okay, too! Every situation is unique and you know your baby best. If your baby is nearing the 3-4-month old mark, I recommend you start working toward it so you don’t feel rushed. Babies change fast!

Now that you know a little bit about how to choose when to move baby to a crib, let’s talk about HOW to transition them!

How to Transition to a Crib: 5 Tips

How you transition your baby to a crib will also include several factors to consider. Here are 5 tips to a successful transition to the crib using the acronym S.L.E.E.P.:

  1. Spend time in the crib – You don’t want your baby’s first experience in the crib to be trying to fall asleep. And, you don’t want them to be surprised when they wake up in a strange place. You want them to feel comfortable in their sleep space so first spend NON-sleep time in it. You can play peek-a-boo, put them in the crib while you put away laundry with music playing, or let them look at a mobile.
  2. Lay them on their backs for safest sleep. This reduces the risk of SIDS. We can’t always make them stay on their backs but that’s the way they should start.
  3. Empty the crib so there are no loose blankets or toys in the crib. It’s considered a safety hazard unless your baby is a year or older.
  4. Ease into it by doing short sleep periods at first. Assuming it’s safe for them to sleep in their previous sleep space, consider working your way up to all sleep periods in the crib. For example, you might start with one nap a day or just bedtime in the crib. Then, when they wake up, you can use the old sleep space. Over a period of a few days to a couple of weeks, you can work your way up to more sleep periods.
  5. Persist through tough times because quite a few of us reject something new. But, after a while, we ask ourselves “Why didn’t I do this sooner?” Your baby might not like the crib, at first. It’s similar to sleeping in a hotel the first night on vacation. At first, the bed just doesn’t feel like our own. Once your baby spends more and more time in the crib, it will feel just like theirs!

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A Special Note for Co-Sleeping Families

If you are co-sleeping or bed-sharing, moving to a crib can be a much bigger step. Up until now, not only was your baby in a different bed, they were also snuggled up to you and, many times, breastfeeding on and off all night. In this scenario, we often build in a few smaller “baby steps” into our Personalized Sleep Plans®. We sometimes have to change sleep associations before we move the baby or toddler into the crib. This is because when you change more than one variable at a time (how they fall asleep AND where they sleep), it is often met with even more protest and crying. Many families will give up due to the very intense reaction. A slower process is often more successful for some families for this reason. You might be interested in reading our article, How to Gently Transition Your Baby From Co-sleeping.

Baby Keeps Waking Up in the Crib

If your baby keeps waking up when you put them in the crib, that may be an entirely different issue. Babies wake for many reasons, including sleep regressions, sleep associations, and more. Be sure to download our free e-Book, 5 Ways to Help Your Child Sleep Through the Night to get started on a better night’s sleep or 7 Common Napping Mistakes to fix those short naps!

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