Countless parents come for help with their 4 month old’s sleep. Why? This article will explain why “good” sleepers sometimes turn “bad” around the 3 or 4 month old mark.
How your newborn baby sleeps in the early weeks
When a newborn sleeps, she cycles between “active” and “quiet” sleep (also known as REM and non-REM sleep), but does not have the distinctive stages of sleep she will have as she grows older and her brain matures. I will avoid too much technical talk because that’s one reason I made this website, so you won’t have to learn the whole history of sleep if you don’t want to (or can’t stay awake to!)), but if you are interested in knowing more about our biological rhythms and how we do sleep in more detail, I highly recommend the book, Solve Your Child’s Sleep Problems), even if you have no interest in “Ferberizing” (just skip that part and consider a no-cry method). Newborns spend a lot of their time in deep sleep, which is why it is hard to wake them up (even to eat!) in those early days, but they do startle when they cycle into “active” sleep, which is one reason swaddling your baby can be so effective.
4 month old sleeps (and sometimes as early as 3 months or as late as 5 months)…
We all go in and out of light and deep sleep. As adults, we might change positions, look at the clock, or reposition our pillow. Up until now, you may have rocked your baby or simply given him a pacifier and he slept for hours without waking up. Well, at 3 or 4 months old, your baby is now sleeping more like an adult. Now when she falls asleep, she does not enter deep sleep right away and if you lay her down before she is in deep sleep, she is likely to wake up and you will start all over helping her to fall back to sleep again and again.
4 month olds enter deep sleep…
Initially in the night, your 4 month old will enter deep sleep relatively quickly, within 30 minutes (this changes as we get older). However, as I said, we all cycle in and out of light and deep sleep. A child’s sleep cycle is about 45-50 minutes. So, your baby will briefly awake 45-50 minutes after she has been asleep. To put that in perspective, if you are holding your baby to sleep, you would need to hold her for at least 30 minutes to make sure she’s in deep sleep and then she might wake up 15 minutes later. Sound familiar?
Overall, though, your baby’s deepest sleep is in the early part of the night, so after that first sleep cycle, she might sleep just fine for a few hours. So, you’re golden right? Just hold her for an hour? Nope!
4 month old sleeps the rest of the night…
The technical definition of “sleeping through the night” is 5 hours of continuous sleep (i.e. no feedings) and many babies can/will do this by 2 or 3 months old. The beginning of the night is your baby’s deepest sleep and after the first 5 hours (if not sooner, depending on just how challenging he is), he will cycle between light and deep sleep, but not as deep as the beginning of the night. This is where the problem of sleep associations really come into play. If your baby needs your help to go to sleep in the beginning of the night, sometime after midnight or so, he will continue to need your help every 1 or 2 sleep cycles (that means every 45 to 90 minutes or as I often hear, every 1-2 hours).
Between 4-6 a.m., approximately, is the lightest sleep of the whole night (parents’ complaints alone make this true, in my experience, aside from my reading). In the very early morning hours (about 30 minutes to an hour before waking up), he will again go into the very deep sleep.
Although babies commonly wake up early, be sure it is truly their waking up time and not just this lighter sleep and that they are having trouble sleeping. You might notice they want a “nap” just 30 or so minutes after “waking up”. What you experienced was a night waking, not starting the day.
4 month old sleep regression
You might have heard about the 4 month sleep regression and wonder if your baby will go back to sleeping well. Some parents will be one of the lucky few whose baby will go back to sleeping well in 2-4 weeks, however, not all of us will be that lucky. For example, I find that babies who need a pacifier to sleep where you are replacing it many times per night do not stop needing that pacifier to sleep. You might get lucky and not have to replace it 10 times (maybe “just” 3-4), but maybe not. It is usually better to solve the root of the problem than to hope you are one of the lucky ones. So, maybe wait a few weeks, but if things aren’t better, plan to make changes. I talk to parents of 8 month olds and even 20 months old who are still waiting for their “baby” to grow out of their sleep problems.
4 month olds sleeping through the night…
How can you help your 4 month old sleeping through the night? Read this website (free article updates via e-mail is a good choice), be sure to check out my free guide, 5 Ways to Help Your Child Sleep Through the Night and/or get a detailed step-by-step baby sleep guide, which includes e-mail baby sleep consultations, to answer all those “what if?” questions.
Download the 4 Month Sleep Regression PDF FREE!
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Share your 4 month old’s sleep story!




thanks for all the advice debbye.i’ve recently discovered that even all the preparations to put him to bed according to schedule have been unsuccessful.he finds it difficult to get back to sleep even when changing positions while sleeping.he hardly naps beyond 20-30 mins during the day, and wakes up at least 7-9 times at night for a minute’s meal of breast milk only to wake up an hour later. im live in nigeria and i’ve wondered if the schedules will apply to own way of life here?
@ Mel- The good news is that sometimes she does only wake once in the night, this is good! Some babies take longer than others to learn to self soothe, up to 5-7 months or even more. So it sounds like you are on the right track. If you are concerned with sticking with this method, then feel free to change it up a little, going in and checking every 5-10 minutes and you can stay with her too if leaving her to cry is too much for you! Good luck!
@ Anthony Oni- Try to stick with your schedule for another week or so, but some babies do have a hard time getting on a schedule until they are a little older. You can try to teach him good sleep habits now by not letting him nurse all the way back to sleep when he wakes every hour. I am sure that Nigeria is different from California where I live, and you can definitely make a schedule that works for you and you life. It may just take a little longer for your son’s sleep patterns to mature and for him to be able to sleep in longer stretches.
Good luck!!!
My lo will be 4 months the 18th. She already wakes about 15 mins to half hour after being put down. Shes been doing this since about 3 months. I typically rock her or hold her and pat her butt till she falls asleep. does this mean shes already going through sleep regression? she will after finally asleep sleep between 4-7 hours then wakes up rooting to nurse then asleep again for another 2 to 3 hours. when she wakes to eat she never fully wakes up but eats a full sitting then lets go and goes back to sleep. Would this already be considered it? also I have tried to get her to sleep earlier. Once in a while she will fall asleep at 8 or 9 but usually she doesnt fall asleep till 1030 or 11pm. she will wake up for the day at around 8am like clockwork. then asleep about an hour or 2 later for her nap. Im wondering if I need to shorten her late nap or wake her up earlier? Help would be great. Thank you.
So I don’t think we has hit sleep regression till last night. She will be 4 months tomrrow and she was up every hour or half hour at a time. She just has to work through this right? Sorry only going 3 hours of sleep just hoping this gets better quick.
Hi Jenell,
It does sounds like 4 month sleep regression and some sleep associations, and this age can often be a difficult one with regards to baby sleep. We don’t usually recommend sleep training until a baby is at least 4 months old and often most babies are not ready until between 5-7 months of age when they have gained a better ability to learn how to self soothe, which is a key skill to them learning how to go to sleep and stay asleep on their own. It is a good idea to works towards feeding your baby at night but not feeding her completely back to sleep. Allow her to finish eating and then lay her back down drowsy but awake, and not rocking or patting all the way to sleep too, so she starts to learn to fall asleep on her own.
Here is a link to our article with the recommended daytime, nap, feeding and bedtime schedule for a 4 month old. You may find it helpful in determining a good schedule for your daughter. Babies tend to wake at the same time in the morning regardless of what time they fall asleep at night, and I would recommend trying to get her bedtime much earlier. Some babies can not handle living on a schedule quite yet, but you can try to move her bedtime earlier by 15 minutes a night.
http://www.babysleepsite.com/schedules/4-month-old-schedule/
And you may find these articles about newborn sleep to be helpful to you now and as a part of starting to teach your daughter good sleep habits too.
http://www.babysleepsite.com/newborns/newborn-sleep-schedule-patterns/
http://www.babysleepsite.com/newborns/newborn-sleep-baby-tips-10/
Good luck!!!
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My 16 week old suddenly went from sleeping 8 hours a night to sleeping a four hour stretch (10 PM – 2AM) then a two hour stretch ((2:30 – 4:30) and then I need to wake her up to go to daycare at 6:30. I was getting really frustrated so I am glad to see that this is normal. I also feel extremely luck that it is only 2 times a night that I have to get up with her not five or six. That would be really difficult to do that and then have to go teach a class room of middle schoolers all day.
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You ladies need to read Dr. Sears! And co-sleep, also do t cry it out! It actually harms baby’s emotional growth! They cry because a need has to be met, if you let them cry without meeting that need they will lear that they can’t trust their caregivers to respond and will stop crying
So it might seem to you that it has worked, but truly it hasnt. Babies this young should not left be alone to fall asleep, they need help with that. I Co slept with my first for a year and I currently co-slerp with my four month old. My first I tried putting g her a crib at 3mos but she slept horribly. She slept best cuddled up beside me, same goes for my son. And I don’t think pacifiers are a sleep association, sucking is a means of comfort for small babies, and pacifiers provide that. My first had a pacifier but gave it up just after a year old, no issues. We need to stop pushing our tiny babies to be so independent and stop trying to get them to fall asleep on their own and stay asleep. They need us alot and its our jobs to meet those needs,no matter how tired we are.
It’s 530am & I’ve been struggling to get my 4 month old back to sleep for the last hour & half. He’s has scheduled feeding times during the day but not overnight & is exclusively breastfed. By 2 months old, he was able to sleep 5 to 6 hours before getting 1 overnight feeding around 3am & would go back to sleep. Shortly after 3 months, his sleep pattern changed where he would wake up consistently around 1am, 3am & 6am but would only be fed at 3am. At both 1am & 6am I was able to use a pacifier to get him back to sleep in about 5 minutes. In this past week, his overnight pattern is still the same but the biggest difference is now he won’t fall back asleep even with the pacifier. Sometimes I let him cry for 5 min before burping him & giving him some water while still in his crib. Interestingly while he’s sitting up he doesn’t cry but the second I lie him back down he cries. Though I can calm him down with his pacifier & favorite toy to the point where he almost asleep, he seems to wake up 5 minutes later making it a viscious cycle. I feel horrible in that I have to tell my other half not to pick him up to soothe him to sleep or bring him to our bed, as I know it will only start a bad habit that I will need to break. Help! I’m not sure if the issue is I’m letting him fall asleep for the night while breastfeeding.
@Ivana Thanks for commenting! I’m so glad you found what worked for you, but I do want you to consider that what worked for you does not work for everyone. It’s great you were able to successfully co-sleep, but for some of us, it just doesn’t work out that well. I was hyper-sensitive I’d roll on top of him or cover him with a blanket or my husband would roll on him, etc. It was not the best sleep, yet better than getting up every 2 hours. However, long-term, it just wasn’t a solution for us. I respect you disagree that pacifiers or breastfeeding all night (human pacifier) are not sleep associations and it’s great that yours gave it up with no problems at one year, but, again, that is not always the case and some wake for a pacifier replacement ALL night. You, personally, may be able to function on waking every hour (though it doesn’t sound like that happened to you) but others can’t function or become ill more frequently, etc. Again, you might want to keep in mind that what you live day-to-day is not what others live day-to-day and try not to judge others for the decisions they need to make for their own families. Thanks again for sharing what worked for you!
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