What is the Moro Reflex?
Understanding the Newborn Startle Response and How to Support It
You’re rocking your baby peacefully. They’re dozing off in your arms — serene, still, soft. Then suddenly, their arms fling out, their legs jerk, and their whole body startles like they’ve been dropped. Their eyes open wide and they cry like they’ve just had a shock.
It’s not you. It’s not them. It’s something completely normal: the Moro reflex.
At Neutral Nest, we’re here to help you understand the early quirks and instinctive behaviours of your baby — with calm explanations and gentle solutions. So let’s talk about one of the most common newborn reflexes, and why it’s actually a sign of healthy development.
What Is the Moro Reflex?
The Moro reflex, often called the startle reflex, is an involuntary reaction that newborns have to sudden changes in their environment. This could be:
A loud sound
A shift in light
A change in position
Or even the sensation of being lowered down
When triggered, the reflex looks like this:
Baby’s arms and legs extend quickly and jerk outward
Their hands may flare open
Then, they quickly draw their limbs back in — often followed by crying
It can look dramatic, but it’s completely normal and harmless.
Why Does It Happen?
The Moro reflex is thought to be a primitive survival instinct, dating back to when infants needed to cling to their caregivers for safety. It’s one of the many reflexes babies are born with — along with sucking, grasping, and rooting.
This reflex is also an important developmental milestone — a sign that your baby’s nervous system is functioning as it should.
When Does It Start and Stop?
Present from birth
Usually strongest in the first 6–8 weeks
Gradually fades between 3 to 6 months old
Should be fully integrated (gone) by 6 months
If the Moro reflex is still strong beyond that point, or seems exaggerated or uneven, it’s worth chatting with your health visitor or GP.
How the Moro Reflex Affects Sleep
If your baby wakes suddenly with a startle during naps or night-time sleep, you’re not imagining things — the Moro reflex often causes early wakings and short naps.
This is why your baby might:
Wake just after being laid down
Cry out suddenly mid-sleep
Flail their arms and seem distressed without any obvious cause
How to Support Your Baby Gently
You can’t stop the Moro reflex — but you can help your baby feel safer and more secure as they adjust to life outside the womb.
1. Swaddle Gently
Using a breathable, snug swaddle can help limit your baby’s flailing limbs and mimic the cosy containment of the womb.
Our Neutral Nest embroidered muslin blankets are ideal for this — soft, organic, and beautifully lightweight.
Note: Always stop swaddling as soon as your baby shows signs of rolling over.
2. Use a Slow, Supported Motion
Avoid sudden movements when placing baby down for sleep. Try:
Lowering baby slowly, keeping them close to your body until the last second
Supporting their head and bottom as you transition them to the crib
Holding them still for a few extra moments once they’re lying down to allow them to settle
3. Try White Noise or Womb Sounds
Sudden noises can trigger the startle reflex. A steady, soothing sound — like a white noise machine or gentle shushing — can help mask environmental shifts and settle baby.
4. Practice Contact Naps (When Safe and Practical)
If your baby struggles to sleep on their own due to the Moro reflex, contact naps can help them get the rest they need while feeling secure. These are also beautiful bonding opportunities — not “bad habits.”
Final Thoughts
The Moro reflex can be surprising (and exhausting), but it’s also a sign of a beautifully developing baby learning how to exist in the world outside your womb. Like so many things in early parenthood, this phase is temporary — and your baby will gradually grow out of it.
In the meantime, meet them with softness. Slow your movements. Swaddle gently. And know that this too shall pass.
At Neutral Nest, we’re here to help you navigate these early milestones with calm, comfort, and confidence — one reflex at a time.