Infant Startle Reflex: What is it & How Long Does it Last?

If you're a new mom, you've probably wondered what the infant startle reflex is. If so, you're in luck! In this post, we'll discuss everything you need to know about the startle reflex in infants. We'll also talk about how long it lasts and what you can do to help your baby overcome it. So, if you're curious about this mysterious reflex, keep reading!

The Startle Reflex: What Is It?

Any parent of an infant knows that one of the most common and seemingly cute things infants do is startle at loud noises, or even just when they are startled awake from a sound sleep. This is called the startle reflex, a normal part of infant development. The startle reflex is also known as the Moro reflex, named after Austrian pediatrician Ernst Moro who first described the reflex in infants. The reflex is characterized by a baby's arms and legs spreading out suddenly. While it may be alarming to see (and hear!), the startle reflex is a sign that your baby's nervous system is typically developing. So next time your little one gives you a little scare, rest assured that it's all part of the process!

Usually, infants are unaffected by their startling. Sometimes it causes them to be awakened or to cry. A baby's cries or unexpected movements might occasionally activate the startle reaction.


infant in shock




Does Your Baby Startle Easily? Here's How to Overcome It

If your infant is startled and screams, they may need some soothing to quiet down. And if your infant is startled, they will not always go back to sleep quickly.

To prevent your infant from awakening abruptly:

  • Before putting your infant to sleep, swaddle them. This will keep their arms and legs close to their torso, preventing them from flailing.

  • Place the infant down gently. Keep your hands on your baby while you lay them down, and then withdraw them.

  • Play white noise in the room (using a sound machine or soothing music) to prevent other noises from disturbing their sleep.

  • Move softly and silently inside the sleeping baby's room.

Have any more questions about taking care of your infant? Visit our blog for the answers you're looking for!

When Does The Startle Reflex Stop?

The startle reaction reaches its apex during the first month of life. Typically, it vanishes at two months of age.

Occasionally, this response might last for three or four months. Some infants continue to startle for even longer, but if your child still has a startle reaction beyond six months, you should see a physician.

If your infant does not seem to have a startle reaction or has it on one side of their body, discuss this with your doctor. This is uncommon and may suggest brain, spinal cord, or nerve disorders.


surprised baby


Related Link: Infant Social Development: Everything You Need to Know

Is The Startle Response Harmful?

While it may sound alarming, the startle reflex is harmless and will go away as the infant matures. It can even be a bit cute to watch! So if you see an infant startle, don't be alarmed - they're just doing what comes naturally.

It is also an essential part of infant development. This reflex helps babies develop their sense of balance and coordination and gives them the instinct to protect their heads and neck. 

Related Link: Things Every New Parent Should Know About Newborn Sleep

Can Older Babies Still Be Startled?

It is common for older infants to be frightened or sensitive to loud sounds. Your infant suddenly screams in response to loud noises because they are new or unpleasant. In addition, it is a natural aspect of their growth.

Infants are more susceptible to noise because their ear canals are smaller than those of adults. This confined area amplifies intense noises even more. Deafening noises may potentially damage your infant's hearing.

Babies also react to noises based on their disposition. A youngster with more sensitivity may weep at the sound of a vehicle horn, but a baby with greater tolerance may not react to an ambulance siren.

If your infant is easily startled by loud noises, turn the volume down on all household gadgets. While your infant is there, speak more softly and turn off loud machines such as the blender.

Babies like white noise, such as the sound of a vacuum, dryer, or baby sound machine. Providing colicky infants with white noise may even prevent them from crying. It is only unexpected loud sounds that frighten them.

Infants become more tolerant of disruptions and commotion as they age. As your child develops and grows used to various sounds, they will likely cease screaming at loud noises.

As mentioned, in most cases, the startle reflex will disappear as the infant grows and matures. However, in rare instances, the reflex can persist into childhood or adulthood. While there is no cause for alarm if this happens, it is always best to consult with a doctor to rule out any underlying medical conditions.

Infants and Their Startle Responses

It's normal for infants to startle when they hear a loud noise. It's part of the infant startle reflex, also called the Moro reflex. The infant startle reflex is when an infant's arms and legs spread out suddenly and then close back up to the body. The infant's startle reflex is normal and happens because the infant's nervous system is still developing. 

Are you looking for even more information on taking care of your little one? Check out 123BabyBox, where you can find more articles!

Related Link: Baby Won't Stop Crying? Here's What to Do

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