Newborn Leg Shaking – My Baby’s Leg Keeps Shaking, Is This Serious?

Shaking, tremors, jitteriness, or jerking movements may or may not be normal in newborns and young infants. It could be part of their normal growth and development or adjustment to life outside the womb. It could also be due to external influences, such as mothers’ substance use or low blood sugar levels. It’s important to rule out seizures and bring the child to the nearest hospital if you’re concerned that it may be a serious condition.

You see your newborn do it again; that strange twitching or jittering of her right leg. It’s happened seven times already today, and you’re afraid it might be a sign of something serious. What could cause a baby’s leg to keep on shaking that way?

It could be normal or something serious

An occasionally shaking leg or arm may be normal in newborns and young infants. In fact, some jitteriness is considered normal in about 40-60% of babies.

This could simply be a fine tremor, but there is always a possibility that this is a sign of other, more serious diagnoses.

Problems with electrolyte or blood sugar levels, hormone levels, oxygen levels, and exposure to unsafe medications are all possible causes of jitteriness or tremors. One way to find out if it’s nothing serious is to place the child in a lying-down position with their arms free on their sides.

Try to offer a pacifier or a gloved finger for the baby to suck. If the tremors stop, then it’s most likely a benign condition.

The cause could be something simple

There may be nothing serious behind the jitteriness. Here are a few reasons for the tremors you see:

Your baby still has an immature nervous system

Does your child’s leg shake or twitch right after falling asleep or while they are asleep? Or does it happen when they cry? Does it last for just a few seconds?

These indicate an immature nervous system that is very typical of newborns. It’s sometimes referred to as myoclonus, which is a quick twitching of muscle fibers. At times, even a quivering chin or lip could also be seen.

Some experts say that this could be due to high levels of norepinephrine, a hormone used by the nervous system. While all babies can have the occasional twitch, this is even more prominent in premature babies.

Nevertheless, myoclonus goes away after a few months.

It’s due to newborn reflexes

Do the jitters happen after your child is startled by a loud noise?

The startle reflex, also called the Moro reflex, is triggered by sudden, loud stimuli such as bright lights and loud noises. Typically, a baby would extend the arms and legs, sometimes even arching the back slightly, for just a few seconds.

This reflex is intentionally built-in as a way for newborns to protect themselves as they adjust to a new environment outside the mother’s womb. The Moro reflex goes away at around 4-5 months of age.

It’s your coffee (and cigarette) use, mom

Are you still breastfeeding but have already included coffee in your diet?

Certain amounts of caffeine that end up in your system can be passed on to your child through breastmilk. Because babies can’t metabolize caffeine as fast as adults do, it stays much longer in their system, leading to a higher chance of side effects.

According to the Australian Breastfeeding Association, breastfeeding mothers can safely take up to 200mg of caffeine per day.

Combining coffee and cigarette smoking while breastfeeding is bad enough in itself. In particular, maternal smoking synergizes with the effects of caffeine on breastfed babies.

The bottom line is to drink only small amounts of coffee and avoid smoking entirely.

It could also be colic

Infant colic usually occurs in children 3 weeks old up to 3-4 months. Some signs of colic include flailing of the arms or legs, with an arched back and legs folded up to the abdominal area.

Sometimes, a parent may confuse this movement with shaking or tremors. Don’t worry; colic is not an illness in itself, and it will go away on its own.

But be wary of these conditions…

On the other hand, there are some serious medical conditions that could be the cause of your baby’s tremors.

Read on to ensure you aren’t missing out on anything that might need medical attention.

Mothers with substance use

Mothers who use certain medications or substances while pregnant (such as alcohol, marijuana, or tobacco use) expose their babies to these substances or chemicals.

After the child is born, their supply of these harmful substances are immediately cut off as the umbilical cord is cut. As a result, they can experience withdrawal symptoms, such as jitteriness.

Your child could have low blood sugar levels

If you’re guilty of not responding to your child’s hunger cues, then they could end up with tremors or shaking because of low blood sugar levels. This is called hypoglycemia.

Crying and jitteriness are late signs of hunger in infants. Don’t wait for your baby to be so hungry, to the point that they’re shaking repeatedly just to catch your attention.

Be sure to rule out a seizure episode

A newborn baby's pediatrician is checking her on an examining table.

This is probably at the top of the list for most parents. While seizures are quite rare in newborns (and are very difficult to diagnose!), they could happen.

Accompanying symptoms are sucking movements of the mouth and repeated eye blinking. If your baby seems to have jerking movements, try restraining that particular limb, or trigger the Moro reflex with a loud sound (like a clap or a bell) — if the jerking continues, have your child seen urgently for a proper medical assessment.


What symptoms should I watch out for?

If your child shows any of the following symptoms, seek urgent medical care:
– Difficulty waking up
– Not moving on their own
– Difficulty breathing, or struggling to breathe
– Bluish or dark discoloration of the face or lips
– Your baby has stopped breathing for 10 seconds or longer, then started breathing again
– You feel that a seizure has occurred

Does an EEG help diagnose seizures in newborns?

Not all cases of seizures in infants need an EEG, especially if there’s a fever associated with the seizure episodes. However, your healthcare provider will determine if an EEG is needed on a case-to-case basis.


Jitteriness or shaking movements are not always abnormal in infants. It could be part of their normal growth and development or are due to minor conditions, such as colic or a mother’s intake of coffee. One of the most serious concerns is the possibility of a seizure.

Observing for additional symptoms can help differentiate a mild from a serious cause of shaking movements. When you still feel in doubt, it’s best to seek medical advice.

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Sarah is a healthcare writer, motivated by her love of reading books while growing up. She took up human biology and further studies in medicine, in order to fulfill her passion for helping kids. While she isn't a biological mother yet, she has taken two young dogs, named Indy and Obi-Wan, under her wing. She would love to someday travel the world and meet kids from different cultural backgrounds.

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