Resources for parents to get through the challenges.

  1. Home
  2. Parenting

Why Does My Baby Shake When Excited?

Babies can do all sorts of weird and wonderful things that can make their parents question if they are developing normally or not.

Some babies will squirm while they breastfeed, walk on their knees or crawl backward instead of forwards. Babies can have behaviors that may at first seem odd but are in fact just a normal part of their development. 

One strange behavior you may have wondered about is why does my baby shake when excited?

Have you ever noticed your baby almost buzzing with excitement when they see a familiar face or when you give them a yummy snack or new toy to play with?

Shaking from excitement is common in babies and in the majority of cases, there is no need to worry if your baby is demonstrating this kind of behavior. 

Is It Normal For Baby To Shake?

It can be alarming to see your baby shaking for the first time, especially if you are a first-time parent.

However, newborns and young babies often make strange jittery movements and may twitch and shake a lot, more often than not this is just part of their normal development and they will grow out of it.

Here are some examples of normal developmental reasons why your baby may shake or make strange movements with their body: 

The Moro Reflex

The Moro or ‘startle’ reflex is extremely common in newborns and young babies. The Moro reflex is triggered when your baby hears a loud sound, or when something startles them.

When the Moro reflex is triggered, your baby’s body will stiffen and they will straighten their arms and open their fists.

The Moro reflex happens when your baby is shocked by a sudden change in their environment (usually a loud sound) and they should grow out of it by the time they are 4 months old. 

Poor coordination

Hand-eye coordination is something babies learn and develop as they grow. Until your baby has mastered the art of moving their limbs around purposefully and smoothly, they may make shaky movements with their arms and legs.

Your baby may make all kinds of weird and wonderful shapes with their body until they have developed the strength and coordination they need to move more ‘normally’. 

Trembling when crying

It is very normal for babies to seem jittery or tremble while they are crying. Your baby may have a quivering lip or trembling chin or their limbs may fly around all over the place, especially their arms.

This is a normal behavior in newborns and young babies and should occur less frequently as your child gets older. 

Immature nervous system

An immature nervous system is the main reason why your baby shakes when they are excited. When your baby is excited by a person, toy, or sound their brain can sometimes send too many electrical signals through their central nervous system.

When this happens your baby will shake and tremble or sometimes flap their arms and bunch their tiny hands into fists.

It can be quite a surprising thing to see for the very first time but if your baby shakes when excited it is not something you need to worry about. As your baby’s nervous system matures and develops they will be able to process their excitement with less shaking and funny little movements. 

Why does my baby vibrate when excited?

Sometimes it can feel like your baby is actually vibrating when excited! This is a very common behavior in babies and is not a reason to be concerned. As we explained above, shaking from excitement is a result of an immature nervous system.

The brain sends too many electrical impulses throughout the body and your baby starts shaking or moving in a jittery fashion. 

If your baby is otherwise healthy and reaching its developmental milestones, there is no reason to let the fact your baby shakes when excited cause you any anxiety.

However, there are certain occasions where shuddering and shaking are a cause for concern and you will need to seek medical attention.

When Should I Be Worried About My Baby Shaking?

It is rarely a causes for concern if you notice your baby shaking. However, shaking is not always a behavior brought on by an immature nervous system, it can be the result of an illness or injury that needs medical attention.

Here is a list of causes of shaking in babies that are not part of normal infant development:


Seizures can cause your baby to shake. Unlike shaking from excitement, the shaking does not stop quickly and is usually accompanied by other seizure symptoms.

If your baby is having a seizure the shaking will continue for more than 20 seconds, their muscles will move in a jerking motion, not just twitching. Your baby’s eyes will also be moving in abnormal ways, rapid blinking, or unusual movements.

Shaking when accompanied by vomiting or a loss of consciousness can be a sign of a seizure and you must seek medical help immediately.

Vitamin D deficiency

Research has found a link between shaking and shuddering in babies and a vitamin D deficiency. If you are formula feeding you will not need to supplement your baby with vitamin D as it is already mixed into their milk.

However, nursing moms will need to give their baby a vitamin D supplement as it is not found naturally in breastmilk.


Shaking and shuddering in babies can cause parents to become concerned that their child may have autism.

There is a large range of symptoms and behaviors that can be linked to autism and as every autistic child will experience the disorder differently, it is not factually accurate to say shaking is definitely a sign of autism.

Some autistic children will flap their arms or shake as a way of self-soothing, however, this is a very common behavior amongst neurologically typical children too.

Shaking alone is rarely reason enough to assume your child has autism. You will need to have your child assessed by a professional who will look at all of their symptoms, not just shaking, in order to determine whether your child is autistic or not. 


What is infant shudder syndrome?

Shuddering attacks (SA) is an uncommon benign disorder that occurs in both infants and young children. Movements resemble shivering and straining but without any impaired consciousness and usually resolve itself or at least improves by the time the child is 2-3 years old.

Baby Cries During Bottle Feeding: Fixing Feeding Problems

Why does my baby stiffen up and shake when excited?

The theory is that your baby is stiffening because they are excited or even frustrated. It is also a part of them discovering what their muscles can and cannot do.

Is it normal for a baby to shake?

I know as a new parent you worry about every single little thing but babies are strange little creatures that do some very odd things from sleeping with their mouth open to day-night confusion. in most cases, the shaking when excited is completely normal and simply part of their development.

The Final Thought 

Seeing your baby shake when they are excited may be a funny thing to witness but can also cause parents some worry.

If your baby shakes when they are excited, rest assured this is part of their normal development and the shaking will stop as their central nervous system starts to mature. 

It is important to remember that babies do not shiver when they are cold like older children and adults do.

If you notice your baby shaking when they are not excited and they are displaying any other symptoms of a seizure, such as vomiting or unconsciousness, seek medical help immediately. 

Shaking from excitement is a normal infant behavior, so soak up those exciting little movements because your baby will grow out of them in no time.