Why Is My Baby Shaking While Sleeping? Is This Normal?

Entering parenthood is one of the most joyous events in life. You have spent the last nine months witnessing the belly grow, the tiny feet kicking, not to mention the ups and downs of pregnancy. Then the day finally comes, and the little bundle arrives.

Like any new parent, you’ve probably prepared yourself for diaper changes, how to give a bath, feeding times and what illnesses to look out for. But with tiny infants, there are bound to be some surprises. Today, we’ll focus on one occurrence that can seem quite scaryshaking and twitching while sleeping.

Why Is My Baby Shaking?

Witnessing your newborn twitching and shaking their hands or feet, or even their neck or mouth, as soon as they fall asleep can be startling. What might come to mind is a seizure, and your instinct is telling you to call 911. But hold the phone, this is actually quite normal.

Newborn babies are going through more changes than teenagers going through puberty. The neurons within their brains are still developing, adjusting to the new world. During a mere year, newborns will learn to roll over, lift their heads, crawl, and giggle, plus maybe even walk and talk.

Shaking or twitching while asleep is, in fact, a common symptom called benign neonatal sleep myoclonus (BNSM).

What Is Benign Neonatal Sleep Myoclonus (BNSM)?

Benign neonatal sleep myoclonus is basically a term used to describe jerky muscle contractions only occurring during sleep. Myoclonus is the medical term used to explain any spasmodic movements within any muscle group. Hiccups, for example, are another form of myoclonus.

In the past, doctors thought BNSM was a kind of seizure, only occurring in newborns. It wasn’t until 1982 that research revealed that this phenomenon was not associated with seizures. Instead, it was something far less worrisome.

Experts still know very little about this occurrence. But they do describe it as a non-epileptic, self-limited movement disorder.

It generally occurs during the newborn’s first few weeks and subsides around two to three months old. However, some may continue experiencing this until three years of age.

BNSM usually begins as the child enters the non-rapid eye movement (NREM) and the rapid eye movement (REM) sleep.

During the NREM stage of sleep, the whole body slows down, and it is generally a dreamless slumber. But upon hearing sounds or sensing movement, the twitching or shaking of a specific muscle group occurs.

Experts now believe that when BNSM occurs during REM sleep, it links to the sensorimotor development. BNSM appears to work as a jump-starter for the brain, activating the circuits in order to teach the newborn about their abilities. When the baby awakens, he or she is already familiar with the movements.

For instance, during the first few days of life, parents can spot twitches in the baby’s hands or feet. As they are getting closer to the milestone of reaching and grabbing, spasms usually occur in the wrists and fingers. Later, jerks may appear in the neck area indicating that baby is getting ready to hold his or her head up.

BNSM has actually opened a window for researchers to understand the baby’s typical development better. This can further help provide crucial clues about neurodevelopmental disorders, such as autism.

Why Does It Occur?

As stated above, experts believe it is a way the body kickstarts the neurons in the brain, preparing it for the next milestone. But in saying this, BNSM is still a newly-discovered phenomenon that requires more research.

The exact reason why it occurs remains a bit of a mystery. Up until recently, the only observations were on baby rats.

One Japanese study suggests that BNSM sometimes links to migraines. During the research, a few of the babies also exhibited signs of migraines, such as cyclic vomiting syndrome.

This, of course, requires more evidence to confirm, as well as a more extended observation period.

Although BNSM is quite common, not every baby will experience it. In that same Japanese study, results revealed that boys were more likely to experience this than girls.

Some evidence points toward genes. Experts found that babies are more likely to experience BNSM if either parent had similar experiences during infancy. Again, this claim requires more research to confirm it. But more studies are now including the medical history of the parents.

How Doctors Diagnose BNSM

When doctors diagnose BNSM, they must rule out other possible conditions, such as epilepsy, or other neonatal seizure disorders. One tell-tale way of knowing if it is BNSM is by waking the baby.

Neonatal seizures cannot be stopped by arousal from sleep. Twitches occurring during BNSM, on the other hand, will subside as soon as the baby wakes up.

To be sure, doctors can order an encephalogram to rule out epilepsy. Both prior to and after the occurrence of BNSM, the brain returns to regular activity. In some instances, misdiagnosed babies received high doses of anticonvulsants. These had little to no effect on the movements.

One study stresses the fact that prescribing these medications without a proper diagnosis can be harmful to the baby. Especially seeing that these often cause drowsiness. Additionally, they can increase the number of episodes.

When to Worry

Of course, seizure-like episodes can also indicate something much more severe.

You should keep an eye out for seizure symptoms. These include abnormal eye movements and continued twitching even after you’ve woken the baby.

If the seizure episode persists for longer than five minutes or your baby exhibits trouble breathing or turns blue, go straight to the ER. These episodes require immediate treatment.

If your baby is having a seizure, never shake him or her. Doing this can cause shaken baby syndrome. Seizures are frightening to witness, but make sure you keep your child still until you medical care can be obtained.


Watching your precious newborn twitch and shake during sleep can ring all the alarm bells. Fortunately, chances are that this episode was nothing more than the harmless phenomenon known as benign neonatal sleep myoclonus.

If your child is exhibiting twitches in limbs, the neck or mouth, you can try gently to wake him or her. However, BNSM is harmless. It is a method used to jump-start the circuits in the developing brain to prepare for the next milestone. And it is, indeed, quite normal.

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