For many families the first year with a baby means broken sleep. Most parents know this is coming. What they do not expect is how long it lasts or how often the baby wakes for no clear reason. If you are awake right now and wondering what you did wrong, here is the first thing to know. Most of what looks like a sleep problem in a baby under one year is normal baby sleep.

This does not make the nights easy. But it changes what you should do. Some night waking just needs time. Some has a cause you can change. A small part needs a doctor. This article explains why babies wake in the first year, what research shows about each reason and what helps.

The goal for this article is to help translate the science of baby sleep into advice you can use because research papers can be sometimes challenging to read when you are sleep-deprived. 

What is normal and what is a real problem?

Every baby wakes at night. So do adults. We wake for a moment between sleep cycles, then fall back asleep so fast that we do not remember it in the morning. A baby has to learn to do this. Sometimes that learning takes most of the first year.

So a real sleep problem is not “my baby wakes up.” All babies wake up. A real problem is when a baby cannot fall back asleep without a lot of help, the waking happens many times a night and the family is very tired.

How normal is night waking? Very normal. One study of nearly 400 babies found that many did not sleep one long stretch even at a year old. With a six or eight hour measure, between 28% and 57% of babies did not sleep through the night at 6 and 12 months (Pennestri et al., 2018). This same study found no link between night waking and a baby’s mental or motor development and no link with the mother’s mood. Babies who woke more were more likely to be breastfed. That is quite logical. Breast milk is easy to digest, so breastfed babies often feed more at night, well into the first year. But waking more is certainly not a reason to stop. Breast milk is very good for your baby’s health. The American Academy of Pediatrics recommends continued breastfeeding to two years or longer, as long as the mother and baby both want it (Meek & Noble, 2022). You do not have to choose between breastfeeding and better sleep. There are many habits that can improve sleep without stopping breastfeeding. And if you want to change night feeds, your baby’s doctor must be involved because they can help you make the change safely.

Why do babies wake so often?

Much of the reason is in the way sleep is built. Every person, baby or adult, sleeps in cycles. In each cycle we move from light sleep into deep sleep and then back toward light sleep again. We repeat this over and over all night long. Near the end of each cycle, sleep is light and a short wake-up is easy. Adults usually do not remember these wake-ups. A baby has to learn (yes, this is a skill) to settle back to sleep alone.

A baby’s cycle is short, about 50 to 60 minutes. An adult cycle is much longer, about 90 to 120 minutes. So a baby reaches that light part of the cycle, where waking is easy, more times each night than an adult does. That is only one reason babies wake more. 

Newborn sleep is built differently, too. A newborn does have sleep stages, but they are not the same as an adult’s. Researchers use three names for them – active sleep, quiet sleep and indeterminate sleep (Coons & Guilleminault, 1982). Active sleep is the early form of REM sleep, the stage linked with dreaming. Quiet sleep is the early form of NREM sleep, which holds the deep sleep. Over the first months these slowly mature. By around three to six months a baby’s sleep starts to look more like the adult pattern of REM and NREM. Fully adult sleep takes years to form.

Newborns need a lot of sleep, about 14 to 17 hours a day, spread across the day and night (Hirshkowitz et al., 2015). From 4 months, babies need about 12 to 15 hours.

Why won’t my newborn sleep at night?

A newborn does not know night from day. The body clock that makes older children sleepy at night (the circadian rhythm) has not fully developed yet. This clock sits in a small part of the brain called the suprachiasmatic nucleus. It runs on a cycle of about 24 hours and sets the daily timing of sleep, the hormone melatonin, body temperature and more. At birth the clock is not yet “running” on a day and night schedule, so a newborn’s sleep is spread across the 24 hours and is driven mostly by hunger.

Newborn sleep does not follow a clear day and night pattern yet. In the first weeks, the body starts building this rhythm slowly. Around 6 to 12 weeks, many babies begin to sleep a little more at night and stay awake a little more during the day. By about 2 to 3 months, melatonin usually starts to rise more at night – this hormone helps the body understand that night is for sleep (McGraw et al., 1999). That is one reason night sleep often starts to improve around 3 months.

Light is the main signal that sets this internal clock that we all have. Light reaches the eye and a nerve path carries the message to the “clock” in the brain. Bright light says day. Darkness says night. In one study of healthy babies, the ones who got more bright light during the day had a stronger day and night rhythm (Tsai et al., 2012). So a bright, active day and a dark, calm night give the clock clear signals. Light is not the only signal. Feeding times, the sound of your voice, your touch and the difference between a busy day and a quiet night are all signals the clock can use.

Some newborns sleep their longest stretch in the day and wake often at night. This is common and it passes. What helps is making the day feel like day and the night feel like night. In the day, keep the room bright, feed and play in the light and let normal house sounds continue. At night, keep the lights low, the room quiet and your handling calm and brief. Over time these signals help the clock settle. They support the change but cannot rush it.

Why does my baby only fall asleep when I rock or feed them?

This is one of the most changeable causes of night waking, so it deserves a careful look.

Many babies wake briefly between sleep cycles. This is normal. The problem starts when the baby does not yet know how to return to sleep without the same help used at bedtime.

For example, a baby may fall asleep in your arms, at the breast or with rocking. Later in the night, the baby wakes in the cot. The arms, breast or movement are no longer there. The baby then looks for the same help again and may cry for you.

Researchers call this a sleep onset association. It means the baby has connected falling asleep with a certain kind of help – for example rocking or feeding . Burnham et al. (2002) found that babies who had a parent present when they fell asleep were more likely to wake and need help during the night.

This does not mean the parent did anything wrong. It only means the baby has learned one way to fall asleep and the good news is that babies can learn a new way with time and some practice.

The goal is to help the baby fall asleep in the same place where the baby will wake later in the night. Put the baby in the cot when the baby is sleepy, but still awake. Stay close and give calm support – there are many sleep training methods and you can choose one that fits your parenting style and your baby’s temperament. Some parents prefer to stay beside the cot and reduce their help slowly. Some prefer brief check-ins. Some prefer very gradual changes with more hands-on comfort at first. The method can look different from family to family, but the main goal stays the same. The baby gets more practice falling asleep in the cot, without the old habit that the parent wants to change.

Over time, the baby learns, “I can fall asleep here. I feel safe” This makes it easier for the baby to return to sleep when they wake up at 3 am.

Is this the four month sleep regression?

Around 3 to 4 months, parents often hear about the “four month sleep regression”. It is a popular term in parenting and sleep apps, but it is not a defined event in sleep science. Research does not show a clear drop in sleep at four months. When infant sleep is tracked across the first year, the nighttime sleep session grows longer, not shorter, with wide differences from one baby to another (Mindell et al., 2016).

What is real is the fact that a baby’s sleep matures around this age. The sleep stages a newborn already has, active sleep and quiet sleep, mature into the adult ones (Coons & Guilleminault, 1982). 

Simply explained, newborn sleep is different from older baby sleep. The sleep stages a newborn already has – active sleep and quiet sleep – over time, active sleep develops toward REM sleep and quiet sleep develops toward NREM sleep. NREM sleep then becomes more organized, with lighter and deeper sleep features appearing over the next months. The amount of REM sleep gradually falls (Lenehan et al., 2023). This is normal growth and not a step backward (like regression).

This change does not happen in one night. It develops over several months. But around this age, many parents start to notice lighter sleep, shorter naps or more waking at night. Many parents feel this change as a sudden drop in sleep and call it the “four month regression”.

So why do some parents notice more waking around this age? Infant sleep changes a lot across these months. It differs widely from one baby to another (Mindell et al., 2016). When a baby does wake more, the waking itself is not always the problem. As you already learned, babies wake briefly between sleep cycles. The harder part is when the baby does not yet know how to fall back asleep without the same help used at bedtime. If the baby needs feeding, rocking or holding to fall asleep, the baby may want that same help again after waking in the night (Burnham et al., 2002).

Such periods of “sleep regression” are not the best time for sleep training. During a change like this your baby needs extra comfort and love. Settle your baby back to sleep in the ways that already work. Keep the days and nights calm and steady and wait for this stage to pass – it usually takes several weeks. After that you can choose a sleep training method that fits your parenting style and your baby’s temperament.

Why did my baby start waking again after weeks of good sleep?

Sometimes a baby sleeps well for a while, then suddenly starts waking more again. One possible reason is a new motor skill.

When babies learn to crawl, pull up, sit, cruise or walk, their sleep can become more broken for a short time. Some babies practise the new movement in the cot. Some wake because they roll, sit or stand and do not yet know how to get back down. Others simply seem more restless during this stage.

Research has found that new motor skills and more night waking can appear around the same time (Scher & Cohen, 2015). This does not prove that the new skill causes the waking every time. It only means the two often happen together.

What can help?

Give your baby plenty of safe time during the day to practise the new skill. If your baby is pulling to stand, practise getting back down during the day too. Keep the bedtime routine steady. At night, give comfort, but try not to create a new sleep habit that you do not want to keep.

This stage often improves once the baby becomes more confident with the new skill. If the waking is very sudden, intense or comes with signs of illness, pain, feeding changes or breathing concerns, it is better to check with your child’s doctor.

Does separation anxiety wake babies?

Around 6 to 9 months, many babies become more aware when a parent leaves. They begin to understand that you can go away and they may want to bring you back. This can make bedtime harder for some babies.At this age, a baby may cry when you leave the room, reach for you more or protest when you put them in the cot. Some babies may wake at night and become upset when they notice you are not there.

Research does support a link between separation distress /separation anxiety/ and sleep problems. One study found that separation distress in 9-month-old infants was linked with more night waking and more time awake at night (DeLeon & Karraker, 2007). Another study found that separation anxiety in 8-month-old infants was linked with bedtime resistance (Kelmanson, 2012).

Separation anxiety can be one reason for more bedtime protest or night waking. But it is not the only reason and the research does not have strong evidence that separation anxiety directly causes every waking. Night waking can come from many things, such as overtiredness, illness, teething pain, feeding patterns, new motor skills or sleep onset associations.

So it is best to see separation anxiety as one possible piece of the puzzle. It may explain why a baby suddenly protests more when you leave, wants more contact at bedtime or cries for you during the night. But again, it should not be treated as the only answer.

There are many gentle ways to help your baby through this stage of separation anxiety. Most of these techniques work best during the day, especially when you combine them and use all of them together.

One of the methods that give the best results is to give your baby plenty of closeness. Hold your baby, play with your baby and answer them when they need you, at bedtime and when they wake in the night. You do not need to worry that you are spoiling your child with love or attention. This stage will pass! Your baby will feel safe again. A child who gets enough closeness in the day finds it easier to settle at night.

Another way to help is to let your baby practice being apart from you in small, gentle steps. You can do this during the day and during the bedtime routine. Once your baby is in the cot, go to the next room for a short moment. From there, keep talking or singing so your baby can hear your voice. This teaches your child that you are still close, even when they cannot see you. Do this often, so being apart slowly gets easier for your child.

Try to make the cot a place your baby is happy to be. Spend a little time there together, playing, singing and cuddling. Mornings and the time after a nap work best, when your baby is rested and content. When the cot feels good in the daytime, it feels safer at night.

When your baby wakes calm and happy in the cot, you do not need to go to them immediatly. Give your baby a few minutes alone. This teaches your child that being alone can feel fine. Over time, it builds their confidence.

How you say goodbye when you leave is important too. Do not leave the room without a goodbye, even for a short moment. Leaving quietly can feel easier, but it can make your baby’s worry worse. When you leave without a goodbye, your baby may start to fear that you can disappear at any time. So always tell your baby that you are leaving and that you will come back. Stay calm and give your child a smile as you go. Keep the goodbye short. If you keep coming back for one more hug, your child may feel that something is wrong.

At night, use the same gentle steps. Keep the same calm goodnight every evening. When your baby wakes, answer them gently and say the same words each time, that you are close and you will come back.

So you understand that what helps during these periods is calm, steady and predictable comfort. Keep the bedtime routine the same each night. Say goodnight in a warm but simple way. When the baby wakes, respond calmly and try to keep your response similar each time.

The message is: “I am here. You are safe. It is still time to sleep.”

The baby is learning that you may leave, but you always come back.

Is my baby overtired?

Parents often say a baby is “overtired” when the baby has stayed awake too long and then has a harder time falling asleep. This can happen, but overtiredness does not explain every hard bedtime or every night waking. 

A better way to think about it is sleep timing.

Sleep depends on two main things. One is sleep pressure – this builds while the baby is awake. The other is the body clock, which tells the baby’s body when it is time to be awake and when it is time to sleep. Researchers call this the two-process model of sleep (Borbély et al., 2016).

This does not mean we can calculate a perfect bedtime for every baby. Babies are not machines and two babies of the same age may need different awake times.

But research does show that timing and routine matter. Babies who fall asleep earlier tend to sleep longer at night (Adams et al., 2020). A steady bedtime routine is linked with better sleep too, including less time to fall asleep, fewer night wakings and longer sleep (Mindell et al., 2015).

You have also probably heard about the “wake windows” – they can help but use them only as a guide. There is no strong study showing that every baby of the same age should stay awake for the same number of minutes. A better approach is to use both the clock and the feedback from your baby. Keep awake times close to what is typical for the baby’s age, but watch your own baby too. If naps or bedtime often become harder after a long awake stretch, try starting the routine a little earlier for several days and see what changes.

Also try to learn your own baby’s early tired signs (like the first yawns and a still, far away look). Use these as a signal and try to start sleep before the baby is overtired.

Does my baby still need to eat at night?

For a newborn, yes. A newborn has a tiny stomach and needs to feed often, day and night. Night feeds are a normal need! This section is not about newborns!

For older babies, things change. Many healthy, growing babies need fewer night feeds or none at all in the second half of the first year. But this is a question for your baby’s doctor. Whether a baby is ready to stop a night feed depends on growth and health. That is a medical decision! If you do reduce night feeds, do it slowly and always follow your pediatrician advice.

Can you keep night feeds and still improve sleep? Yes, you can.

Better sleep does not always mean removing every night feed. Some babies still need a feed at night, but they can learn to go back to sleep more easily after that feed. The goal is not to ignore hunger. The goal is to avoid feeding becoming the only way the baby can fall asleep after every waking.

For example, a baby may need one planned night feed, but not need feeding every 45 minutes. A calm feed in the night can stay. At the same time, you can work on the bedtime routine, the sleep environment, sleep timing and sleep onset associations. Research links steady bedtime routines with better sleep, including less time to fall asleep, fewer night wakings and longer sleep (Mindell et al., 2015). Research on infant sleep also shows that how a baby falls asleep at bedtime can matter for night waking and self-soothing (Burnham et al., 2002).

So the question is not only, “Does my baby need to eat at night?” A better question is, “Is my baby waking from hunger or is feeding the only way my baby knows how to return to sleep?”

If your baby still needs a night feed, keep it calm, quiet and boring. Feed the baby, then return to sleep. If your baby wakes again soon after a full feed, look at the other sleep factors too.

Could a health problem be keeping my baby awake?

Most baby sleep trouble is normal development or a learned habit. A smaller part comes from a health problem. It helps to know the common ones, so you can ask your baby’s doctor about them. One note first – several of these get blamed far more often than they should, so they are worth checking with a doctor.

Reflux. Yes, it can disturb sleep in some babies. But it is blamed much more often than it is the real cause. Crying, back arching and night waking are common in all babies and most are not caused by reflux. Reflux and cow’s milk allergy overlap a lot, which makes both easy to misread (Salvatore et al., 2021). Always ask a doctor before you treat for reflux.

Cow’s milk protein allergy. Cow’s milk protein allergy is real, but it is not as common as many parents think. A large European study found confirmed cow’s milk allergy in less than 1% of children (Schoemaker et al., 2015). But parents suspect cow’s milk allergy much more often. In some reports, close to 1 in 10 babies are suspected to have it, but cow’s milk allergy is much less common (Vandenplas et al., 2024). This matters because the signs can be confusing. Crying, fussiness, reflux-like symptoms and broken sleep can happen with cow’s milk allergy. But they can happen for many other reasons too (Munblit et al., 2020; Salvatore et al., 2021).

A baby seeming better after removing milk does not prove allergy. The baby may improve for another reason or the timing may only look connected. So do not remove cow’s milk protein without medical advice. A doctor should guide the process. If allergy is possible, the doctor may suggest a short milk-free trial and then a safe reintroduction to check whether milk was truly the problem.

Iron deficiency. Low iron can sometimes be part of the sleep puzzle, especially when a baby has iron-deficiency anemia. Research has found that 6-month-old babies with iron-deficiency anemia can show more movement during sleep, more time awake at night and differences in sleep organization (Angulo-Kinzler et al., 2002; Peirano et al., 2010). Some sleep differences have also been found later in childhood in children who had iron-deficiency anemia as babies, even after the anemia was treated (Peirano et al., 2007). This shows a link, not proof that low iron causes every sleep problem.

Parents should not start iron supplements without medical advice. Too much iron can be harmful! If you are worried about iron, speak with your baby’s doctor. The doctor can decide whether testing is needed.

Eczema. Eczema, which doctors call atopic dermatitis, makes the skin itch and the itch breaks sleep. It often starts in the first year. In babies with eczema, more severe skin is linked with worse sleep for the baby and the mother (Harbottle et al., 2024). Treating the skin well is the first step, with a doctor.

Breathing problems. Pauses in breathing or loud snoring during sleep are not common in babies, but they need a doctor’s check. Tell your doctor about any noisy or hard breathing in sleep.

The common point is simple – all of these belong to your baby’s doctor, not to a sleep plan! Feeding and health questions are outside what sleep advice can answer.

Is teething keeping my baby up at night?

Teething often gets the blame for bad nights in the first year. Sometimes it may bother a baby. But it probably gets more blame than it deserves.

A large 2025 study followed 849 babies aged 3 to 18 months. The study used crib cameras and computer analysis to measure sleep. It compared nights around tooth eruption with other nights. The measured sleep did not really change. Babies did not sleep less, they did not wake more and parents did not visit the cot more often (Kahn et al., 2025).

Here is the interesting part. More than half of the parents said teething had disturbed their baby’s sleep. But the measured sleep data did not show the same thing (Kahn et al., 2025).

Older research also suggests we should be careful before blaming everything on teeth. A large review found that the most common teething signs were sore gums, irritability and drooling (Massignan et al., 2016). Another study did not find strong links between new teeth and clear groups of symptoms (Wake et al., 2000).

This does not mean teething never bothers a baby! A baby may have sore gums, chew more, drool more or seem more unsettled for a short time. The 2025 study measured sleep in the cot, so it cannot rule out every short moment of discomfort.

The point is simple – do not assume teething is the whole answer, especially if bad sleep lasts for weeks. Look at the whole puzzle because the baby may have a strong sleep association, a new movement skill, a schedule problem or a health issue that needs a doctor’s advice.

What actually helps a baby sleep better?

This is where things can start to get better. It is a small set of habits that research supports and that fit the way a baby’s body works.

Keep a calm, steady bedtime routine

When you follow the same few steps every night, in the same order, your baby learns what comes next and starts to settle before sleep. The research here is strong and it grows with use. A study of more than 10000 children aged 0 to 5 found a dose effect – the more nights a family kept a steady routine, the better the children slept. They fell asleep faster, woke less often and slept longer (Mindell et al., 2015). A wider review found the same benefits across sleep, mood and family life (Mindell & Williamson, 2018). Your routine does not need to be long. A short, calm set of steps works well, for example a bath, a feed, a book, a song and then the cot. 

Make the sleep space safe and sleep-friendly

A safe sleep space is a good sleep space. The current advice from the American Academy of Pediatrics is clear – place your baby on their back to sleep, on a firm, flat surface, in your room but not in your bed for at least the first six months, with nothing soft in the cot (Moon et al., 2022). That means no loose blankets, no pillows and no toys, so a baby under one year should not have a blanket or a soft toy in the cot during sleep. If you want to keep your baby comfortable, a baby sleep sack does this safely and it works as a great comfort object.

Sleep environment also matters – keep the room dark at night and dress the baby appropriately.

Help your baby learn to fall asleep alone

This skill is behind most calm nights. The goal is for your baby to fall asleep without your help, so they can fall asleep again by themselves when they wake in the night.

The gentlest way to start, at any age, is to place your baby in the cot when they are sleepy but still awake, after your usual calm routine. Over time your baby learns to fall asleep in the cot, which is where they wake in the night.

After the newborn stage, parents who want a more active method have safe options with good research behind them. These methods help babies fall asleep faster and wake less often.

What is the best sleep training method?

The best method is the one your family can actually follow. Some methods are gentler and some are firmer, but a plan you cannot follow for more than two nights will not help anyone.

Build a steady sleep-wake rhythm

Build a steady sleep-wake rhythm across the day – not a fixed clock schedule. The time a baby can stay happily awake between sleeps is called an awake window. It is short in a newborn and grows as your baby gets older. The number of naps slowly falls across the first year.

Use awake windows as a starting point and let your baby’s tired signs guide the rest. A baby who is awake too long becomes harder to settle. A baby placed in the cot too early is not yet tired enough to sleep. The goal is a rhythm that fits your own baby, with awake windows and naps that grow as your baby grows. A steady daytime rhythm keeps day sleep and night sleep working together.

The work behind a good night

You have just read how many different reasons a baby can have for waking at night. Knowing what is normal, what is a habit, what is a passing stage and what needs a doctor is the daily work of a child sleep consultant. It takes a clear understanding of how baby sleep grows and a set of safe methods that can fit any family.

Families everywhere need this help. Tired parents often do not know who to ask. Pediatricians treat the medical side and often send families to a certified sleep consultant for the daily coaching. When you help a family move from broken nights to restful nights, you change how their whole home feels. There are few kinds of work where you can help so much in so short a time.

This is what we train our students to do. They learn the science of infant sleep, every safe method from no cry to let cry, how to understand each family, how to build a plan they can follow and how to support them with care until it works. Our students come from many backgrounds. What they share is patience and a wish to help. Students study at their own pace from anywhere. 

The first year is hard on sleep for almost every family. Most of it gets better on its own, some gets better with a few steady habits and a small part needs a doctor. Knowing which is which is most of the work. If your own sleep stays broken even after your baby settles, our post on why you are still awake after the baby sleeps covers that.

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