As a new parent you quickly come to recognise your baby’s cries in the night.

By the time they’re a few months old you are tuned into the cries that signal when they need feeding. And you begin to learn which cries mean that your baby is uncomfortable and which tell you that they have wind or need changing.

But what do you do if your baby starts to cry in the night, suddenly and as if in distress but doesn’t wake? Are they having nightmares? Are they hurt or poorly?

These sudden cries or whimpers when your baby is sleeping can be worrying but they’re often not a cause for concern.

When your baby cries suddenly but doesn’t fully wake up

A baby who cries in the night because they’re hungry or wet or cold or even poorly will usually keep on crying. They don’t tend to cry out for a moment and then fall back asleep. Their cries may escalate in volume to alert you that they need you to attend to their needs. To put in bluntly your baby will usually let you know (loudly) if they need you.

Sometimes though your baby cries in their sleep suddenly and alarmingly. Or they might whimper in their sleep for a minute. But they don’t fully wake up.

Your automatic response is to think they need something and hearing these sudden cries in the night can make you begin to worry that something is wrong.

But there could be a number of reasons why babies cry in the night. First it helps to understand how babies sleep.

How a baby’s sleep patterns differs from our own

Babies don’t sleep in the same way as adults. As grown ups sleep we go through cycles of lighter sleep (with REM – Rapid Eye Movement), when our brains are more active, and periods of much deeper sleep.

Adult sleep cycles last around 90 minutes each. We barely notice passing from one sleep cycle to the next. Baby sleep cycles only last about 50-60 minutes, meaning they are naturally more restless sleepers.

When your baby is in the shallower cycle of sleep – the REM stage – they are more alert and can jerk, twitch and kick their arms and legs.

Because babies have immature neurological systems they can stir easily as they go from one sleep cycle to another. And as they do they might cry out or whimper in their sleep. This is all natural. If you watched an adult sleep, they would also be more restless in this stage of sleep – it’s just that we don’t often stay awake to witness it.

Babies are still getting used to the sudden changes in their sleep cycles which means that they can cry out or whimper as they pass from deep sleep to REM. Often they will cry out for a moment and then settle back down.

But if you hear the sudden cry as a parent you can sit up like a shot and worry that your child is distressed. Often your baby will cry out loudly and suddenly but not wake fully and, if they are not disturbed, they will fall back asleep.

What can these cries mean?

They could be a sign of a busy little brain

Babies have a lot of new sounds, sights, experiences and feelings to process each and every day. Each one is new to them. It’s an incredibly large amount of new information to process and their brains are busy trying to understand it all.  

The brain works hard during sleep to process new memories and file away all sorts of new information. Because your baby has so many new experiences to process they can be overloaded. This can mean that they cry out or whimper in their sleep as all these neurological processes go on.

Your baby’s night time cries might be just a sign of them filing away all the new things they have learned that day!

Could my baby be having nightmares?

Sometimes your baby can cry out in their sleep and sound so distressed and frightened that you might wonder if they are having a nightmare.

Experts are still divided on whether babies even dream, let alone have nightmares. Many believe that because of limited life experiences and an immature brain that dreams and nightmares are not possible for babies.

Psychologist David Foulkes, one of the world’s leading experts on pediatric dreaming, believes that babies don’t dream for their first few years of life.

He believes that REM sleep (which is when adults dream) serves a very different purpose for babies. Instead of dreaming in this stage of lighter sleep when their brain is more active, Foulkes believes babies use this stage of sleep to spend this time building pathways in their brain.

Their brain makes sense of the world around them and what they have learnt and later helps them learn language.

Even though your baby might cry in their sleep and sound distressed or alarmed, chances are they are not having a nightmare. They could just be filing away all the new information their little brains have soaked up that day.

Developing bodies that wake up babies

As babies grow they learn all sorts of new physical skills and begin to roll over, sit up and stand up. These discoveries are new and exciting and change the way your baby sees the world.

As your baby goes through each new discovery it can interrupt their sleep. At around 4 months your baby might learn to roll. If they go from one sleep cycle to another they might roll over and cry as they go from one position to another.

Some of these changes might mean baby wakes up entirely.

For example, at around six months your baby might learn to sit. When they reach lighter sleep cycles they might try to sit up. This can end up waking them and they can cry out for you. 

Or at 9 months they begin to be able to pull themselves up and stand. Again they might wake up and decide to try out their new found skills during sleep and suddenly want their Mama.

Babies who are learning to babble and speak can also wake up to practice their new found skills, whatever the hour. Learning new skills is an exciting time for a new baby and their brains are super charged as they learn.

Don’t be surprised if your baby tries out his new found skills in the middle of the night and calls to you to witness his achievements.

What to do if your baby cries during the night

Often you will know if your baby is crying for a feed or because he needs a nappy change or is uncomfortable. New parents become quickly attuned to their baby’s cries and needs. But when your baby cries in his sleep suddenly and as if in distress and doesn’t even seem to wake it can seem worrying.

Give them a minute or two to settle

If your baby cries out in the night wait a minute or two to see if they settle. Even though you’ve been awakened by a louder cry, chances are they will settle back to sleep on their own.

Stroke their back

If your baby keeps on crying it might help to gently stroke them and settle them back to sleep. Keep things quiet and boring so your baby doesn’t get confused and wake up fully and think it is morning.

If they continue to cry, feed or change baby

If your baby is really in distress or needs feeding or changing then they usually cry out for longer than a minute or two to let you know. If, on the other hand, it’s a case of them transitioning between sleep cycles, they will probably go back to sleep quickly.

Always seek medical advice

If your baby cries often and inconsolably in the night and there are no obvious reasons then always seek medical advice, even if it’s only to put your mind at ease.

Your baby may be suffering discomfort like reflux or colic which is causing them to cry out in their sleep. Your GP or health visitor will be able to look into this and other potential causes.

Even if all medical reasons are ruled out but your baby cries often in the night it’s always worth talking to someone. A medical professional might spot something important or they might reassure you that nothing is wrong and be able to suggest things you can do to help your baby sleep better through the night.

If you’ve ruled out any medical concerns, and know that your child simply needs you to help them fall asleep again, you may want to consider sleep training. 

A good program to try is the Sleep Sense program which walks parents through the process in a detailed but also flexible way.