Baby cries in their sleep - common causes and tips

Why does my baby cry in their sleep?

It's common for babies to wake up and cry at night, but sometimes they also cry in their sleep with their eyes closed, seemingly still asleep.

You might have heard your baby whimper, whine, or cry in their sleep, only to find them peacefully sleeping when you check on them. Or maybe you've witnessed your baby cry loudly or even scream with their eyes closed, only to quiet down and continue sleeping without fully waking up.

While this isn't very common, it's also not entirely unusual. But what causes this phenomenon?

Four common reasons

1. Your baby is in the active sleep stage

Before 3-5 months of age, babies don’t have sleep cycles and stages like adults do. Instead of four sleep stages, they only have two: quiet sleep and active sleep. Babies spend about half of their sleep time in each stage during their sleep cycles.

Quiet sleep is like our deep sleep. During this stage, babies quietly and still, with rhythmic and regular breathing. They look calm and peaceful, usually without any facial expressions.

Active sleep is your baby’s version of REM sleep, but unlike adults, their body isn’t paralyzed during this stage. You might notice your baby twitching their arms and legs, grimacing, making sucking motions with their mouth, babbling, or even crying.

It’s very easy to mistake a baby in active sleep for being awake. In fact, it’s so common that parents often accidentally wake their baby when they’re actually still fast asleep.

2. Your baby is transitioning from one sleep cycle to another

Everyone goes through sleep cycles at night, moving through different stages. For adults, these cycles are about 90-120 minutes long, but for babies, they’re much shorter—around 30 minutes for newborns and 50-60 minutes when they’re a few months old. Between each sleep cycle, we briefly wake up. Sometimes we open our eyes, sometimes we don’t. We usually don’t remember these brief awakenings unless something memorable happens or if we stay awake for a longer period.

Waking up between sleep cycles is a survival mechanism, likely because it helps us check if the environment is still safe. It also keeps us from sinking too deeply into sleep, where it might be harder to wake up.

For babies, crying is one of their most important ways of communicating, so it’s always close at hand. When your baby is between sleep cycles, possibly transitioning from active sleep to a brief awakening, they might cry without even opening their eyes and then fall right back asleep.

3. Your baby is sleeping restlessly

Many parents notice that their baby sleeps more restlessly and cries more often when they’re overtired or overstimulated. This can happen because their baby’s nervous system gets overwhelmed by all the stimuli, and when they’re overtired, stress hormones are released, which can disturb their sleep.

With Napper, you can easily keep track of when your baby’s next nap should happen and help prevent overtiredness.

4. Your baby is uncomfortable

Another reason a baby might cry more often in their sleep is if they’re uncomfortable. If your baby is in active sleep or between sleep cycles and something is bothering them, like a wet diaper that feels cold, they’re more likely to cry in their sleep.

Could it be night terrors?

Night terrors are most common in preschool-aged children but can, in rarer cases, also occur in babies. However, knowledge about night terros in babies is limited since their occurrence in children under 1.5 years old hasn't been studied much.

Night terrors are considered a partial awakening, meaning the child is partially awake but still stuck between sleep and wakefulness. Most often, their eyes are open, but they’re unresponsive.

The episode usually starts with a scream, and the child appears frightened and panicked. They may sit up, flail their arms, sweat, and seem unaware of their surroundings. In younger children, nightmares might look a bit different, like inconsolable crying.

They typically last about 10-20 minutes and stop when the child falls back asleep. The best approach is to calmly help them settle back to sleep. The next morning, they rarely remember what happened.

If night terrors are frequent and intense, it’s a good idea to talk to your healthcare provider or seek medical advice.

What can you do when a baby cries in their sleep? Should I comfort the baby?

As a parent, you know best when it comes to comforting your baby—trust your instincts! Usually, when your baby cries with their eyes closed for any of the reasons mentioned above, it’s only for a short time before they fall back asleep on their own. It’s often okay to wait a little while and see if they settle back to sleep.

Can babies have nightmares?

It's impossible to know for sure, and it also depends on a baby’s age. Many people believe that newborns aren’t fully capable of dreaming yet, but the truth is, we just don’t know. Slightly older babies who experience REM sleep may be more likely to have dreams.

My baby suddenly cries in their sleep—is that also normal?

Yes, when a baby cries in their sleep, it can happen suddenly and often stops just as quickly. However, if your baby cries out suddenly, it’s a good idea to check and make sure they're not in pain. For example, if your baby is sleeping in your arms, their arm be stuck or uncomfortable.

When should you contact a doctor?

If the baby occasionally cries in their sleep as described in this article, it’s usually completely normal, and you typically don’t need to contact a healthcare provider about it.

Talk to your healthcare provider if you feel that your baby cries excessively, or if you’re worried about your child’s health or behavior for any other reason.

Q&A

My baby cries in their sleep with their eyes closed—what does it mean?

Babies can cry with their eyes closed if they are in a sleep stage called active sleep. It can also happen if a baby wakes up briefly between sleep cycles and then falls back asleep. The reason may also be that they became overtired during the day or that they're uncomfortable.

My baby cries in their sleep but isn’t awake—what does it mean?

If your baby cries in their sleep but isn’t awake, it could be because they're in the active sleep stage. During active sleep, your baby may grimace, make sounds, move their arms and legs, and even cry. It could also be because they're is between sleep cycles or something is making them uncomfortable.

What does it mean when a baby cries in their sleep?

A baby crying in their sleep can mean different things. If the cause is that your baby is in active sleep, it can happen reflexively and may not have any particular significance. Sometimes the cause may be that a baby became overstimulated or overtired during the day or that they are uncomfortable.