Why Does Your Baby Fling Their Arms Out Like They’re Skydiving? All About the Moro Reflex
Have you ever noticed your baby suddenly fling their arms wide, fingers splayed, as though they’ve just jumped from a plane? It can look startling—especially when it seems to come out of nowhere—but this dramatic little movement is actually a completely normal part of your baby’s early development.
This reaction is called the Moro reflex, and it’s one of several primitive reflexes that babies are born with.
What is the Moro reflex?
The Moro reflex—sometimes called the startle reflex—is an automatic reaction to a sudden change in a baby’s environment. This might be a loud sound, a sudden movement, a shift in their position, or even the feeling of falling as they’re lowered into their cot. In response, your baby will fling out their arms, open their hands, and sometimes cry. After a moment, they’ll usually draw their arms back in and settle again.
It’s one of those things that can surprise you as much as it surprises them!
Why do babies have the Moro reflex?
The Moro reflex is thought to be a protective survival response. From an evolutionary point of view, it may have helped infants cling to their caregiver if support was lost.
Although babies don’t need to cling on in the same way today, this reflex is still present at birth as part of the neurological wiring of the brainstem. It’s a good sign that your baby’s central nervous system is developing typically.
When does it appear and disappear?
The Moro reflex is present from birth and typically fades between 3 and 6 months of age. It’s one of the reflexes your health visitor or paediatrician may check during developmental assessments.
If the reflex doesn’t seem present at all, or if it persists beyond 6 months, it’s worth chatting to your healthcare professional, as it could indicate a need for further assessment.
How can I support my baby through it?
The Moro reflex is automatic—you can’t stop it happening—but you can help your baby feel more secure when it does.
Tips to support your little one:
-
Swaddling in the early weeks can help reduce the startle and promote better sleep.
-
Hold your baby close when lowering them into a cot or pram to avoid sudden movements.
-
Respond with calm and comfort—a reassuring voice and cuddle can settle their startled feelings.
What does it mean for baby development?
Reflexes like this one are building blocks for your baby’s movement and coordination later on. As the Moro reflex fades, it’s usually replaced by more purposeful, voluntary movement—like reaching, grasping, and eventually rolling.
This is a sign that the frontal lobes and motor cortex are beginning to take over from the primitive reflex centres. It’s all part of the beautiful, layered development that we celebrate each week in Baby College classes.
