Does your baby startle at every sound? Struggle with tummy time? Have coordination that feels… off? There might be a neurological reason many healthcare providers never check for.
What Are Primitive Reflexes?
Primitive reflexes are automatic neurological responses that babies are born with (some even emerge in utero). They serve critical survival and developmental purposes.
You’ve probably seen these reflexes in action:
- Rooting reflex – Baby turns toward touch on their cheek to find breast or bottle
- Grasp reflex – Baby automatically grabs your finger
- Moro reflex – Baby startles with arms flinging out at loud noises
These reflexes are completely normal and essential for your baby’s development.
The Critical Point: Reflexes Must Integrate
Here’s what every parent needs to understand:
Reflexes are NOT meant to stay active forever.
They’re designed to do their job for a specific period, then integrate back into the central nervous system by specific ages.
For example:
- Moro reflex should integrate by 4-6 months
- ATNR should integrate by 6-7 months
- STNR should integrate by 9-11 months
Once integrated, these reflexes become the building blocks for more complex movements and cognitive tasks—everything from walking and running to reading, writing, and playing sports.
When a reflex persists beyond its intended period, it’s called a “retained” or “unintegrated” reflex—and it can cause significant developmental challenges.
What Causes Retained Reflexes?
The most common reason: Inadequate tummy time and missing typical developmental milestones.
Here’s why:
When your baby is on their tummy pushing up on forearms while tracking objects side to side, they’re not just strengthening muscles. That movement is actively integrating reflexes like the ATNR.
The movements that integrate reflexes:
- Tummy time with visual tracking
- Rolling both directions
- Crawling on hands and knees
- Rocking in quadruped (hands and knees) position
The modern baby gear problem:
Baby walkers, jumpers, reclined seats, and excessive time in car seats (outside the car) interfere with normal movement patterns and directly disrupt reflex integration.
These devices prevent the natural movements your baby’s nervous system NEEDS to mature properly.
The Impact of Retained Reflexes
Research shows that retained reflexes can cause:
- Reading and writing difficulties
- Language and speech delays
- Decreased concentration and focus
- Poor coordination and balance
- Sensory processing challenges
- Emotional regulation issues
Important: Having a retained reflex does NOT mean your child will have all these challenges. But addressing retained reflexes early can help prevent or reduce struggles down the road.
3 Key Reflexes Every Parent Should Know
1. ATNR (Asymmetrical Tonic Neck Reflex) – “Fencer’s Pose”
Timeline:
- Appears: 13 weeks after conception
- Should integrate by: 6-7 months
What it does:
- Acts like a corkscrew to help baby move down birth canal
- Develops eye-hand coordination
- Builds the corpus callosum (bridge between brain hemispheres)
- Develops vestibular system (balance)
What it looks like: When baby’s head turns to one side, the arm on that side extends while the opposite elbow bends (like a fencer’s stance).
Signs of retention in babies:
- Can’t bring hands to midline (center of body)
- Can’t suck or chew on hand when head is turned toward it
- Poor coordination during crawling and walking
Signs of retention in older children:
- Difficulty developing a dominant hand
- Poor coordination tracking and catching balls
- Vision and reading difficulties (ATNR is the #1 reflex linked to reading challenges)
- Over 50% of children with retained ATNR have dyslexia
- Handwriting difficulties and hand cramping
- Child may twist entire torso to keep arm straight while writing
- Uses excessive pressure when writing, causing fatigue
These kids aren’t being difficult. Their nervous system is working against them.
2. STNR (Symmetrical Tonic Neck Reflex)
Timeline:
- Appears: 6-9 months
- Should integrate by: 9-11 months
What it does:
- Develops near and far vision (head down = near vision, head up = far vision)
- Develops binocular vision (using both eyes together)
- Helps baby get into quadruped (hands and knees)
- Allows upper and lower body to move independently
What integrates it: Rocking back and forth on hands and knees.
This is why the STNR is often retained in children who don’t crawl—they never engaged in that rocking movement.
What it looks like:
- When baby raises head: arms straighten, legs bend, bottom lowers onto ankles
- When baby lowers head: arms bend, legs straighten
Signs of retention in babies:
- Uncoordinated crawling
- “Bear crawling” with straight arms and legs (instead of hands-and-knees)
Signs of retention in older children:
- Poor posture (stooped shoulders, bent knees, flexed hips)
- Legs wrapped around chair legs when sitting
- Prefers lying on floor instead of sitting on furniture
- W-sitting position (cross-legged is uncomfortable)
- Difficulty swimming (unsynchronized leg movements)
- Difficulty switching between near and far vision (whiteboard to paper)
- Poor eye-hand coordination (catching balls)
- Poor impulse control and concentration
These aren’t behavioral issues. These are neurological issues that can be addressed.
3. Moro Reflex – “Startle Response”
Timeline:
- Appears: 9-12 weeks in utero
- Should integrate by: 4-6 months after birth
What it does:
- Helps baby move down birth canal and take first breath (via adrenaline release)
- Produces automatic response to sudden stimuli (loud noises, bright lights, sudden touch)
What it looks like:
First pattern: Baby arches head back, lifts arms up and back, spreads fingers, gasps for air
Second pattern: Baby curls forward, pulls legs and arms toward center, cries
Signs of retention in babies:
- Startles at the SLIGHTEST sound
- Cries frequently and requires constant soothing
- Can’t be put down without distress
- Every little noise sends them into crisis
If you have a baby like this, you know how exhausting it is. You feel like you can’t put them down. Every sound is a trigger.
Signs of retention in older children:
- Visual challenges and difficulty ignoring irrelevant input
- Motion sickness, poor balance and coordination
- Living in constant fight-or-flight state (excessive cortisol production)
- Panic attacks, mood swings, aggressive outbursts
- Biting, pinching behaviors
These children aren’t being “bad” or “difficult.” Their nervous system is stuck in survival mode. They’re literally perceiving threats that aren’t there because their Moro reflex never integrated properly.
Why Movement Is the Answer
Here’s the incredibly good news:
Movement is the ultimate driving force of brain health and growth—in infants, children, and adults.
The science:
- Movement causes nerve cells to multiply and strengthen their connections
- Exercise activates brain-derived neurotrophic factor (BDNF), which converts stem cells into new neurons
- Exercise literally nourishes brain tissue
- Children with more cardiovascular activity consistently outscore less-active children on academic tests
Movement isn’t just about physical health. It’s about cognitive health, emotional health, and neurological health.
The Cerebellum Connection
Remember from Episode 5: The cerebellum isn’t just responsible for balance and coordination—it’s ALSO responsible for:
- Eye tracking
- Cognition and problem-solving
- Behavior and emotional regulation
The same part of the brain that processes movement also processes learning.
This is why floor time, crawling, and free play aren’t “just for fun.” They’re building your child’s brain for everything they’ll do in life.
[Related: Episode 5 – Why Crawling Matters]
What to Do If You Suspect Retained Reflexes
For Infants (Birth to 12 Months)
The best news: Following the developmental milestone checklist will help your baby naturally integrate reflexes.
Action steps:
- Prioritize daily tummy time (short, frequent sessions)
- Maximize floor time over baby equipment
- Support your baby through each milestone sequentially
- Don’t skip stages or rush development
- Limit time in walkers, jumpers, bouncy seats, and reclined chairs
Movement IS the medicine.
[Download: FREE Ultimate Baby Motor Milestone Checklist]
For Toddlers and Older Children
Please don’t feel like you failed.
Retained reflexes are incredibly common. Even as a pediatric OT, my own children have retained reflexes we’re working on integrating.
Half the battle is just knowing what retained reflexes are and why they’re important to integrate.
The good news: Your child’s nervous system is incredibly capable of change. Even if milestones were missed, even if reflexes are retained, it’s never too late to give your child’s brain what it needs.
What’s coming: I’m creating a course specifically on what to do if your child has signs of retained reflexes. It will include specific movement activities, exercises, and strategies you can do at home to help your child’s nervous system catch up.
[Stay updated: Subscribe to WeeThrive Weekly Newsletter]
Key Takeaways
✅ Primitive reflexes are normal, necessary, and present from birth (or in utero)
✅ Reflexes MUST integrate by specific ages or they cause developmental challenges
✅ The most common cause: inadequate tummy time and missed motor milestones
✅ Baby equipment interferes with the natural movements needed for reflex integration
✅ ATNR is the #1 reflex linked to reading difficulties and dyslexia
✅ STNR affects posture, vision switching, and coordination
✅ Moro reflex retention causes constant fight-or-flight state and emotional dysregulation
✅ Movement is the key to reflex integration at ANY age
✅ Floor time beats baby gear every single time
✅ It’s never too late to support your child’s nervous system
Resources
📥 FREE Ultimate Baby Motor Milestone Checklist
[Download here – LINK]
🎧 Episode 2: Birth to Independent Sitting
[Listen here – LINK]
🎧 Episode 3: Crawling to Walking
[Listen here – LINK]
🎧 Episode 5: Why Crawling Matters
[Listen here – LINK]
📧 WeeThrive Weekly Newsletter (updates on courses and resources)
[Subscribe here – LINK]
Your Questions Answered
Q: Can retained reflexes be fixed in older children?
A: Yes! The nervous system is capable of change at any age. Specific movement activities can help integrate reflexes even in school-age children and beyond.
Q: How do I know if my child has retained reflexes?
A: Look for the signs listed above for each reflex. A pediatric occupational therapist or physical therapist can perform a formal reflex integration assessment.
Q: Will my child definitely have problems if they have retained reflexes?
A: Not necessarily. Severity varies, and early intervention makes a huge difference. Some children compensate well; others struggle significantly.
Q: Can baby gear really cause retained reflexes?
A: Excessive use of equipment that restricts natural movement (walkers, jumpers, seats) prevents babies from getting the sensory-motor experiences needed for reflex integration. It’s about balance—occasional use is fine, but floor time should be prioritized.
Q: My baby missed tummy time due to reflux. What now?
A: It’s not too late. Start where your baby is now and work through the milestone sequence. Even older babies and toddlers can benefit from going “back” to practice foundational movements.
Final Thoughts
If you suspect your child has retained reflexes, please don’t panic.
You haven’t failed.
The fact that you now know about retained reflexes puts you ahead of 90% of parents. Knowledge is power, and armed with this information, you can give your child’s nervous system exactly what it needs to thrive.
Whether your baby is 2 months old or your child is 8 years old, it’s never too late to support healthy neurological development through movement.
Have questions about retained reflexes? Join the WeeThrive community and connect with other parents navigating infant and child development.
[Join WeeThrive Weekly Newsletter – LINK]
About the Author
Sarah Cook is a pediatric occupational therapist (MOTR/L), business owner, and mom of three boys—including one with Down syndrome and one who experienced developmental delays due to missed early milestones. She created WeeThrive to give parents the therapy knowledge and tools they need to support their child’s development at home, without waiting months for early intervention services.
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