Why baby wakes EVERY 2 HOURS. All night long.
Two hours seems to be the magic (and dreaded) number of hours many babies will sleep before waking again. All. Night. Long.
You might have noticed (we certainly have) that this tends to happen more beyond the 4 month mark, but it can certainly happen for younger babies too. This article looks at the key factors behind why your baby might be waking every 2 hours overnight, especially from midnight onwards.
Please note that we are not referring to newborn babies waking for feeds every couple of hours, which is quite normal and expected. Instead, we are referring to those babies who had maybe started sleeping longer stretches at night, between 4-6 hours at a time, and then suddenly started waking every 2 hours. Or babies who have been sleeping well between bedtime and midnight and then waking 2-hourly after that, or babies who have continued to wake 2-hourly well beyond the newborn stage.
We also have to say that the purpose of this article isn't to discourage feeding your baby overnight or to advise you to force your baby to sleep through the night if they aren't ready. We simply want to share our knowledge of what can cause this overnight change in your baby's sleep cycles and some possible ways around it, if you're interested.
Our Little Ones App helps to take the guesswork out of why your baby is frequently waking overnight and gives you access to Certified Sleep Consultants in the Little Ones Village if you need further support.
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Let's start by looking at your 6-12 week old baby:
Your baby's sleep and sleep cycles are still relatively immature at this age. They will more easily drift between sleep cycles in the day, meaning you can often achieve nice long naps (although some babies can actually have too much sleep during the day!).
By around 6 weeks, your baby will hopefully have started consolidating their sleep into more noticeable awake and nap periods in the day and might well have begun sleeping in longer stretches overnight. Their night-time sleep cycles at this age are around 4-6 hours long, and this is why your baby might start doing these longer stints at night, waking just once or twice for a feed. When this happens, you feel like a new person again after coming through the tricky and exhausting newborn phase!
Suppose that hasn’t happened, and your baby is waking every 2 hours overnight. In that case, there are many possible reasons for this, including hunger, under or over tiredness, their startle reflex waking them, trapped wind, reflux or an issue in the sleep environment. We’ll go through some of these factors in more detail towards the end of this article.
By around 12 weeks, some babies will have been sleeping like champs, sometimes even through the whole night! Until...
Somewhere around 4 months (aka the sleep regression):
Beyond 12 weeks and around 4 months, your baby's sleep neurology matures. This is commonly called the 4 month sleep regression as it certainly appears to be a regression in their daytime napping and their night-time sleep, especially if you'd gotten used to the longer sleep stretches at night.
What happens at this point is your baby's sleep has dramatically changed to be more organised into defined sleep cycles. The daytime cycles change first - your baby's level of arousal between their daytime cycles is increased, meaning they can start to fully wake at the end of each sleep cycle, which is around 45 minutes.
Sound familiar? This is known as catnapping: sleeping for one sleep cycle at a time, all day long. Read our article for more info on catnapping and some ways around it. At this point, your baby, although catnapping in the day, might still be doing good long chunks of sleep overnight. Many people are happy to tolerate the shorter day sleeps because the nights are still manageable. Until that changes too...
Around 4 months, your baby may start waking every 2 hours overnight because their sleep cycles have matured and shortened to be just 2 hours in length, after which they will enter a very light sleep phase and easily wake, often needing help get back to sleep. The solution to this is to encourage "self-settling" so that your baby can happily drift off back to sleep on their own.
Waking up at night between 4-6 months:
Between 4 - 6 months, if your baby is already self-settling, you may experience them having a noisy resettle every 2 hours where they will wake and cry briefly and then go back to sleep. If they aren’t self-settling yet or something else is bothering them, they will often wake up completely and need your help to go back to sleep. Every 2 hours.
Once your baby has reached the sleep milestone of their daytime and night-time cycles maturing, their sleep habits and sleep associations really come into play. This means that if your baby has learnt to go to sleep by being actively settled, i.e. by you feeding or rocking them to sleep or by using a pacifier (that they cannot yet replace themselves), they will start to need that method replicated every time they wake between sleep cycles in the day (45 minutes) and at night (2 hours); it is the only way they know how to go to sleep and go back to sleep.
Many babies this age can learn sleep cues and associations to help them fall asleep without the need to be actively settled; things such as white noise, having a dark room, a consistent bedtime/nap routine and having age-appropriate awake times are all great ways to encourage your baby to self-settle to sleep.
Self-settling means that your baby can happily drift off to sleep independently when all the conditions for sleep are lined up. They will also be able to resettle themselves back to sleep when they naturally wake between sleep cycles in the day and overnight, meaning that they no longer need you to actively settle them back to sleep.
Baby waking after midnight:
Many babies will sleep soundly from bedtime until midnight, when we all have our deepest, most restorative sleep, then begin to wake 2-hourly after that. Parents will often assume that this isn't a settling issue, seeing as their baby can "self-settle" in the earlier part of the night. But, unfortunately, it's more to do with the huge physiological drive to sleep that occurs in the first part of the night.
Between bedtime and midnight, your baby is being pumped full of the sleep hormone melatonin, and their body is pushing them strongly towards sleep. They begin their night well, sleeping deeply until around midnight when the melatonin starts to drop out of their system. It continues to diminish between midnight and 7 AM and its total disappearance in the morning (as well as a rise in cortisol) is the thing that cues us to wake up. Researchers at The University of the Balearic Islands in Spain have even found that babies fed a special ‘night-time’ formula that contained tiny amounts of melatonin slept better in the hours after midnight.
After midnight, your baby is far more prone to waking fully after each sleep cycle simply because they're in a lighter sleep. So if they cannot settle themselves back to sleep or if anything is bothering them such as hunger, being too hot or cold, sickness, too much light in their room, or they are over or under tired, they will be very unsettled each time they naturally rouse and need you to put them back to sleep. Every 2 hours. All night long.
So what can you do to encourage some longer stretches of sleep overnight?
Under or Over Tiredness
The first (and easiest) thing you can do to improve the 2-hour waking is to ensure your baby isn't waking for reasons that are quite easy to control - such as having too much or too little day sleep. These factors will result in an unsettled baby between sleep cycles. Our Little Ones App will steer you in the right direction for the best times/lengths for your baby's naps to lead to much-improved night-time sleep.
Hunger is also an obvious cause of night waking in a baby; however, beyond 4 months, your baby shouldn’t need to be feeding 2-hourly overnight, especially if they are able to go longer than this between feeds in the day. If you find your baby is waking and having a few sucks then falling back asleep, it is more likely that they are wanting to suck themselves back to sleep rather than needing the milk for nutrition purposes.
Our Little Ones App has several gradual, responsive methods to help your baby learn to go back to sleep without needing you to feed them every 2 hours.
You can also try making tweaks in your little one's sleep environment as a quick and easy fix. We would recommend having a very dark room with no nightlight (until your little one is over 2 years old), using continuous white noise all night long and keeping their nursery the ideal temperature for sleep - around 18 degrees Celcius / 65 degrees Fahrenheit.
We also recommend making sure babies under 5 months (who aren’t rolling yet) are still swaddled, as this is proven to help them sleep better. Or, use a baby sleeping bag for older babies so they can't kick their blankets off and get cold. Our product recommendations page has excellent swaddles, sleeping bags and blackout blinds.
Above all else, your best line of defence against the 2-hour wake is to encourage your baby to self-settle at the start of naps and at bedtime - then resettles during the night should naturally follow suit.
Our Sleep Programs have helped over 100,000 parents and babies in this exact same situation to gently and effectively resolve 2-hourly night waking. Helping your baby towards the best sleep possible for them is something you can certainly achieve; all the information you need is in our Little Ones App.
"My baby was a good night sleeper but a bad day sleeper. Then when she was 4 months old everything changed. She suddenly was waking up 5 times a night and I was losing my marbles fast! The sleep deprivation was really getting to me. I bought this Program and I can not recommend it more highly! I've suddenly gone from a horrible sleeping baby to a baby who is tired on cue and sleeping 11 hours a night. I can not express what a relief it is to know that this works. I was sceptical and hoped it wasn't people just preying on desperate mothers/parents, but I am a real customer from Brisbane Australia who is happy to say it was the best money I have spent!" - Sally from Australia
St James-Roberts I, Roberts M, Hovish K, Owen C. Video Evidence That Infants Can Resettle Themselves Back to Sleep After Waking in the Night, as well as Sleep for Long Periods, by 3 Months of Age. J Dev Behav Pediatr. 2015 Jun;36(5):324-9. doi: 10.1097/DBP.0000000000000166. PubMed PMID: 26035139; PubMed Central PMCID: PMC4459553.
Coons S, Guilleminault C. Development of sleep-wake patterns and non-rapid eye movement sleep stages during the first six months of life in normal infants. Pediatrics. 1982 Jun;69(6):793-8. PubMed PMID: 7079046.