When Does the Startle Reflex Go Away?

You know the drill: your baby is peacefully asleep in your arms, you approach the crib and start to lower them down as gently as you can, and then — wham! — they fling their arms out, arch their back, and start crying.

Welcome to the wonderful world of the startle reflex.

Also called the Moro reflex, it’s a totally natural response that babies have as they get used to being in the world as a new human.

So when does the startle reflex go away?

While it’s not the same for everyone, here’s what you might expect.

In this article: 📝

What is the startle reflex?

When newborns get a fright — caused by anything from a noise to a bright light to their own movement — the startle reflex kicks in. And it usually looks like this:

They first extend their limbs and neck out wide, and then they bring their arms back together in front of their bodies.

Sometimes they cry.

Sometimes they cry a lot.

And sometimes not at all.

Because newborn babies can’t yet support the weight of their heads, the feeling of their heads falling back or forwards may startle them.

In some cases, this reflex is in response to a feeling that they are falling, which can happen when you pick them up or put them down.

At what age does the startle reflex stop?

Like most things baby, no one timeline fits everyone exactly.

But according to the American Academy of Pediatrics, the startle reflex tends to start disappearing at around two months old. [1]

And while it may seem a little alarming to witness at first, it’s all part of your baby’s healthy development.

In fact, reflexes are something your doctor will look for at your early checkups. [2]

Some other reflexes they might test for are:

• Rooting and sucking, in response to their instinct to find food.
• Grasping, where they wrap their fingers around something that is put into their hands — think a toy or an adult finger. (This one should be illegal for its cuteness.)
• The fencer’s pose. With arm outstretched and their head turned to one side, they bend their other arm in the opposite direction.

Why does my 3 month old startle so easily?

If your three-month-old gets startled, it’s likely that they’re still at the mercy of the Moro reflex.

By about four months, your baby’s neck should be able to support the weight of their head.

And this means they can proudly hold their heads up high — and hopefully not startle themselves too much.

If the startle reflex hasn’t gone away by the time they reach six months old, check in with your doctor to see that nothing else is up.

How do you break a baby's startle reflex?

The startle reflex is natural in a newborn, so it’s nothing to worry about when your baby is young.

But — and this is a big one — this reflex may startle them awake even when they are sleeping on a flat surface with no other disturbances.

And that may mean that neither you nor they get much-needed rest.

Never fear! There are ways to keep your baby from startling themselves awake.

Enter the swaddle.

This soothing practice has been around for centuries.

It involves wrapping a thin blanket around your baby like a burrito, which resembles the comfort of the womb.

With all their limbs tucked away, it’s harder for them to startle themselves awake.

And if you want to know how to stop the startle reflex without swaddling, the best thing to do is to try and avoid triggers.

Because the startle reflex can be activated when we lay our babies down, it can help to keep them as close to your body as possible when doing so.

And then putting them down softly while supporting their head so it’s the last part of their body to touch the mattress.

And where possible, avoid loud noises and bright lights that might give them a fright.

(We know — far from always possible. Do what you can.)

Within a few months, the startle reflex should disappear on its own.

You’ve got this.

And if you need some support along the way, connect with your Peanut community.

We don’t have to do this alone. ❤️