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Why Do Babies Laugh-In Their Sleep: What Causes It?

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When Do Babies Start to Laugh

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Also known as hypnogely, laughing in sleep is a common occurrence in babies that at times leads to multiple questions on the minds of parents, also becoming an event to note the baby’s first laughter in your baby book!

In most cases, newborn baby laughing in sleep isn’t harmful, however, in a few cases could also indicate a sign of a neurological issue.

The Understanding Of REM Cycles

It is important to understand the baby’s laughter when they sleep, which is mostly bifurcated into two kinds: (1) rapid eye movement or REM, and (2) non-REM sleep. 

While asleep, a baby can go over multiple cycles of REM and non-REM sleep. To help you understand better, Parenthoodbliss researched  three stages of non-REM sleep :

  • Stage 1 – This is when the baby goes from being wide awake to asleep, rather quickly and short. Here the rate of breathing slows down, the muscles tend to relax, and the waves of the brain slow down.
  • Stage 2 – This indicates light sleep, that is, just before the later deep sleep. Here, the heart and the breath further slows down and the muscles relax more as compared to before. Adding to this, the movement of the eyes under your lids stops and the activity of the brain slows with sporadic periods of electrical activity.
  • Stage 3 – In order to feel refreshed, this stage of sleep is required. It occurs more in the first half of the night where the brain waves, heartbeat, and breathing are at the lowest point.

On the other hand, REM sleep is where most of the “dreaming” occurs. It starts for about an hour and a half after you’ve fallen asleep. Here, the eyes tend to move quickly, back and forth under the eyelids and the brain waves vary but are close to what they were like when they wake.

Adding on, in REM sleep, the breathing is irregular and the heartbeat and blood pressure are similar to when you’re awake with legs and arms temporarily paralyzed. The reason behind this is to prevent you from acting out to what you may be doing in your dreams.

Similarly, laughs in your sleep are experienced during REM sleep, although these are instances that occur in non-REM sleep as well. At times, this is referred to as parasomnia – a kind of sleep disorder that is caused by abnormal movements, emotions, and perceptions that take place during sleep.

Baby Laughing In Sleep: What Causes It?

When a baby laughs in their sleep, in most cases, as discussed above, there is no reason to worry. As per the reviews in 2013, laughing in sleep is the most harmless physiological phenomenon which is experienced with REM dreaming and sleep. Despite this, it can also be experienced during non-REM but is rare.

REM Behavior Sleep Disorders

In rare situations, laughter during sleep could be a serious sign, such as REM sleep behavior disorder. Here, the paralysis of the limbs doesn’t occur in sleep but the baby acts out the dreams physically.

This can include laughing, talking, shouting, and ending up with the baby waking up during the incident, remembering the dream. This sleep behavior disorder can also be associated with other disorders like Parkinson’s disease and Lewy body dementia.

Parasomnia

This laughter during sleep can also be associated with the non-REM sleep arousal parasomnias. In other and simpler words, this could also mean or indicate a situation where the baby is half-awake and half-asleep.

Parasomnias include sleep terrors and sleepwalking, which are short episodes with most others lasting for less than an hour. 

This is quite commonly seen in children which can also affect or can be experienced by adults. 

Are there any risks of parasomnia?

Here are causes that can be experienced with an increased risk of parasomnia:

  • Sedative use
  • Genetics
  • Sleep deprivation
  • Stress
  • Altered sleep schedule

Newborn Baby Laughing In Sleep: What Causes It?

There is no clear cause as of now that can determine the cause or reason behind a baby laughing in sleep. It could be the baby’s dream, although they do experience an equivalent of the REM sleep cycle, also known as active sleep.

As it’s nearly impossible for anyone to know if the cause was the baby’s dream in the first place, it’s commonly believed that when the little munchkin’s laugh in their sleep, it is, in most cases a reflection or a response to a dream that they are presently having. 

For instance, parents may note that babies tend to twitch or even smile in most of their dreams when they are in their active sleep. In these kinds of sleep cycles of the infant, the bodies are capable of making involuntary movements that could contribute to the little one’s smile and laugh at this time.

In the rarest and rare instances, there are a few cases where the baby could experience seizures that occur and they experience situations like uncontrolled giggling – also known as gelastic seizures. These are rather short seizures that are expected to last for around 10 to 20 seconds that can be expected to start in infancy at around 10 months old. 

These gelastic seizures can be experienced when the baby is falling asleep, or when they are fast asleep and wake up due to the effect. In case you notice that your baby is facing these on a regular basis or is experiencing the same multiple times in a day with vacant stares or there are grunting or unusual body movements or squirming, we highly recommend consulting a pediatrician to be sure of the situation and prevent any unforeseen dangers in the little one.

Yes, the diagnoses could be fairly tricky and in most cases, the doctors would expect to know more regarding the situation, they might also run some diagnostic tests in order to be sure of what’s going on.

Newborn Baby Laughing In Sleep Final Conclusion

While most incidents mentioned above could be fairly tricky, and at times scary, understand that it is only rare and in most cases, there is nothing to worry about. 

Especially for babies, laughing in sleep is typical and generally not a cause for concern or worry for parents, keeping in mind that the incident is not accompanied by any kind of abnormal behavior by the little one that could come across as dangerous and typically an incident occurred “out-of-the-blue.”

In case you are experiencing any form of sleep disturbances or are experiencing troubles with sleeping, and especially when accompanied by an abnormal activity, we’d 100% recommend consulting a doctor about the concerns/incidents. There is a possibility for them to refer the baby to a sleep specialist for further evaluation, however, the bottom line of it all would be to have the issue addressed for the betterment of all.

Newborn Baby Laughing In Sleep FAQs

1) What are the three stages of non-REM sleep?

  • Stage 1 - This is where the baby goes from being awake to asleep, rather quickly and short. Here the breathing slows down, the muscles tend to relax, and the waves of the brain slow down.
  • Stage 2 - This indicates light sleep, that is, just before the later deep sleep. Here, the heart and the breath further slows down and the muscles relax more as compared to before. Adding to this, the movement of the eyes under your lids stops and the activity of the brain slows with sporadic periods of electrical activity.
  • Stage 3 - In order to feel refreshed, this stage of sleep is required. It occurs more in the first half of the night where the brain waves, heartbeat, and breathing are at the lowest point.
  • 2) What does REM behavior sleep disorder include?

    This can include laughing, talking, shouting, and ending up with the baby waking up during the incident, remembering the dream. This sleep behavior disorder can also be associated with other disorders like Parkinson’s disease and Lewy body dementia.

    3) What are the risks of parasomnia?

    Here are causes that can be experienced with an increased risk of parasomnia:
  • Sedative use
  • Genetics
  • Sleep deprivation
  • Stress
  • Altered sleep schedule
  • 4) What is a parasomnia in babies?

    This laughter during sleep can also be associated with the non-REM sleep arousal parasomnias. In other and simpler words, this could also mean or indicate a situation where the baby is half-awake and half-asleep. Parasomnias include sleep terrors and sleepwalking, which are short episodes with most others lasting for less than an hour.

    5) What is a gelastic seizure? Is it normal in babies?

    There are a few cases where the baby could experience seizures that occur and they experience situations like uncontrolled giggling - also known as gelastic seizures. These are rather short seizures that are expected to last for around 10 to 20 seconds that can be expected to start in infancy at around 10 months old.

    6) Why is the baby laughing in sleep?

    Parents may note that the babies tend to twitch or even smile in most of their dreams when they are in their active sleep. In these kinds of sleep cycles of the infant, the bodies are capable of making involuntary movements that could contribute to the little one’s smile and laugh at this time.

    On behalf of the editorial team at Parenthoodbliss, we follow strict reporting guidelines and only use credible sources, along with peer-reviewed studies, academic research institutions, and highly respected health organizations. To learn about how we maintain content accurate and up-to-date by reading our medical review and editorial policy.

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