Baby Startle Reflex: What It Is & How Long It Lasts

Baby Startle Reflex: What It Is & How Long It Lasts

Have you ever seen your baby give off a look like they have been startled? You may see them suddenly extend their arms and legs and then pull them back in again. This probably happened after a loud sound or if you suddenly changed your baby’s position. 

This set of motions is referred to as the baby startle reflex and is a completely normal reflex during your baby’s first few months of life. 

Are Baby Startle Reflex and Moro Reflex the Same?

Yes! The baby startle reflex and Moro reflex are the same. You may hear the terms used interchangeably, but know that they are describing the same effect. 

The Moro reflex was given its name as it was first described by a pediatrician named Ernst Moro. Fun fact, Dr. Moro was a gifted pediatrician who encouraged the sterilization of bottles. He also developed a carrot soup recipe that helped treat children with debilitating diarrhea. 

Why Baby Startle Reflex Isn’t a Bad Thing

Although it may be startling to see your baby’s Moro reflex triggered, this is actually a good thing. An active Moro reflex signals that your baby’s nervous system works just as it should. 

Your sweet little one is brand new to the world, and they are adjusting to all the sights and sounds like a champ. Although your baby may startle themselves after this reflex is triggered, you are there to provide a comforting cuddle and sweet words to comfort your sweet little one. 

Common Moro Reflex Triggers

Although it can be a little startling to see your baby get startled, it is a completely normal and expected stage for newborn babies. Let’s look at the different ways your baby’s Moro reflex may be activated, and how you can help your baby along the way. 

Babies Are Startled by Unexpected Movements

Imagine your baby has fallen asleep peacefully in your arms. You’re ready to lay them down in their sleep space, pop some popcorn and catch up on your Netflix queue. As you lay your baby down, they arch their back and fling their arms and legs out. They’ve woken themselves up, and they are not happy campers. Chances are, neither are you.

The transition from arms to bed is a common trigger to activate your baby’s Moro reflex. When you lay your baby down to sleep, your baby now has less contact with your supportive body, and they may feel a sensation of falling. 

To keep your baby from waking themselves up when you are laying them down, try keeping your baby as close to your body as long as you can. 

The key is to only change your grip once their back and head is gently placed on the mattress. This will help prevent that free-falling sensation and help them stay asleep during this transition. With a sleeping baby safely tucked in bed, you can peacefully binge-watch that show you’ve been putting off.

Loud Noises Are Scary for Babies

While your baby was in the womb, they were enclosed in a space that was soft and warm. While we want to imagine it was a quiet place, it wasn’t completely silent, as your baby could hear blood whooshing around mom’s body, heartbeat, and digestive system sounds. Outside sounds were muffled by mom’s body tissue within the womb, so although your baby could hear some things, they were not exposed to loud sounds. 

Now that your baby is out in the real world and out of their comfortable, snug place, they have to get used to the bright lights and blaring noises that we know as being a part of the real world. 

As your baby’s parents, you are there to keep them safe and protected. Your baby comes into the world without any knowledge of fear or dangers, and they are just getting used to the senses that will help them interact with the world as they grow. It is fun to watch your baby explore the world around them, but of course, there are always speed bumps to maneuver. 

Like a slammed door or a neighborhood dog barking, sudden noises can startle babies. This can cause your baby’s Moro reflex to be activated. Of course, your baby’s response to being startled may be to cry. Your baby is not aware of where the noises are coming from or what is even making the noises. As your baby learns more about their surroundings, being startled by loud noises will slowly become a thing of the past. 

If there is a tendency for loud noises to occur while your baby is sleeping, using a white noise machine can help drown out these noises and keep your baby snoozing peacefully. 

Babies Can Scare Themselves

Do you have a pile of laundry in your room that makes you look twice in the middle of the night? You catch sight of it, and your fight-or-flight response goes into gear, trying to figure out what is making up those dark shadows. Then you realize it’s just laundry and laugh at yourself. It still takes a few minutes to get back to a calm state to sleep. 

With your little one, they can also scare themselves – but instead, they may scare themselves awake. The Moro reflex is triggered if your baby senses a quick or sudden movement or hears a loud sound. If your baby is asleep, their own flailing of those little arms and legs can be a surprise to your baby, and they can be jarred awake. After this, it may be hard for your baby to get back to sleep, which is not fun for anyone in the household.

Swaddling is an effective way to help keep your baby from waking themselves up, as it keeps your baby snug and safe. Snugly wrapping your little one in a comfy blanket mimics the environment your baby experienced in the womb. It also helps to keep your baby’s arms and legs from flailing about if their Moro reflex is activated. 

If you decide to swaddle, remember to lay your baby on their back to sleep. It’s also important to avoid swaddling your baby too snugly. To ensure that your baby is perfectly snug as a bug, make sure that you can fit a few fingers between their blanket and body. 

Sometimes, Babies Get Scared for No Reason

Your baby is adjusting to this loud and bright world as best as they can. The new sights, smells, tastes, and feelings can sometimes be overwhelming. New situations are occurring all the time, and your baby may want to cling to the things that they know best, parents being the best example. 

When exposed to a new experience, your baby may be fearful as they do not know what to make of this new sight, sound, or feeling. If the experience is a loud or quick one, your baby’s Moro reflex will alert you that your baby has been startled. Your baby may need some comfort with a quick cuddle and reassuring word that everything will be alright. 

When Does the Moro Reflex Go Away?

We know you don’t want to talk about your baby growing up already, but as they grow, you’ll see that the Moro reflex fades away by around six months. You may see it start to fade away as early as four months, and its departure usually coincides with your baby being able to hold their head up on their own. 

What Other Reflexes Does a Baby Have?

Your baby has different types of reflexes that aid in their survival. The presence of these reflexes also indicates that all is well when it comes to your baby’s neurological development. 

The Sucking Reflex

Your baby intuitively knows how to suck when something is placed inside their mouth. This instinct allows your baby to feed on a bottle or breast. This reflex develops in the womb, around 32 to 36 weeks. 

You may even witness this on ultrasounds if you catch your baby sucking on their thumb in the womb. This reflex can use up a lot of energy, especially for preemies who may have been born before 36 weeks. Lactation consultants are fantastic experts to turn to when your preemie needs a little support. 

The Grasping Reflex

The grasping reflex may be one of your favorites. By stroking the palm of your little one’s hand, you’ll trigger this reflex, and your baby will close their fingers automatically. This will look like they are holding your finger. 

This is a sweet reflex that you may actively trigger on purpose when you want to hold your sweet baby's little chubby hand. We would definitely do the same! 

This reflex starts to fade away around six months of age. While we love automatic hand-holding, this signals that your baby’s motor skills are developing right on track. 

The Rooting Reflex

The rooting reflex helps your baby find food. If you stroke your baby’s cheek or mouth, you can see this reflex in action. Your baby will turn their head in the direction they feel any touch. The baby’s mouth will open, and they will begin to root around to find a food source, whether it is a bottle or breast. On average, this reflex will disappear around four months. 

In Conclusion

Reflexes are a vital part of your baby’s development. Their little nervous systems are brand new and need some time to develop. These involuntary actions are nature’s way of preparing your little one to best interact with their brand new environment. 

When it comes to the Moro reflex, being proactive with swaddling and the use of white noise machines can help your little one from reacting to any stimuli that may trigger the reflex. This can help prevent any self-wakeups in the middle of the night. 

We love a peaceful, snoozing baby.

Here at Little Yawn Collective, we are big fans of sleep. We champion sleep and its unique role for healthy childhood development. We want to help encourage good sleep habits through the use of consistent bedtime routines, as science says good practices lead to better sleep.

Our products are made to fit into your little buddy’s sleep routine and are melatonin free. Check out our Snooze Bundle, which contains products you need for your child’s bedtime routine. 

In our SnoozeBundle, you will find our Soothing Shampoo & Body Wash with Calendula, our Nourishing Body Lotion with Oat & Shea Butter, and our Relaxing Pillow Spray. Each product is infused with our NaturalSnooze fragrance. Comforting lavender, bergamot, cedarwood, chamomile, coconut, and sweet almond are blended to create a relaxing and dreamy effect for your little one. This fragrance is proven to create an environment that helps you fall asleep and stay asleep. 

The best part of our products is that they fit in your routine seamlessly, no matter your baby’s age. As you continuously change your baby’s bedtime routine to meet their needs, we are right there to support you so your baby (and you) can rest easy. 



When can a fetus hear? Everything you want to know | Medical News Today

What scares kids, age by age, and how to soothe them | CNN

Newborn Reflexes | Stanford Children's Health

Moro Reflex - StatPearls | NCBI Bookshelf

Palmar Grasp Reflex - StatPearls | NCBI Bookshelf


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