What Is the Moro Reflex?
The Moro reflex, often referred to as the “startle reflex,” is one of the many primitive reflexes present in infants from birth. It is a physical reaction to sudden stimuli in a baby’s environment—most frequently a response to sound or movement. For example, when an infant is laid down suddenly or hears a loud noise, you might observe their arms and legs quickly extending outward before retracting in, almost as if they’re trying to cling to their caregiver.
This response isn’t just about movement; there’s often an emotional component as well. The startled baby may let out a cry after being surprised. This sudden outburst—both physical and vocal—isn’t random. The Moro reflex serves the vital purpose of alerting a caregiver to potential danger or distress. When an infant is startled, the response is powerful enough to prompt quick action from those nearby, helping to keep the baby safe and secure.
The Moro reflex triggers a release of stress hormones such as cortisol throughout the baby’s body, pushing them into a classic “fight, flight, or freeze” state. These chemicals heighten alertness and readiness for action in response to danger, even though the “danger” might be as innocuous as a gentle shift in the child’s position. Once the caregiver reassures and comforts the infant, those stress hormones dissipate, and the baby returns to a calm state.
Typical Timeline of Development of the Moro Reflex
The Moro reflex follows a fairly predictable developmental path in human growth. This reflex develops in utero and remains active for about the first six months of life. In a typically developing baby, it is integrated at that time into a more sophisticated startle response that does not involve the dramatic limb extension seen in newborns. As integration occurs, the baby’s nervous system gradually replaces this automatic, whole-body reaction with more controlled, higher-level nervous system responses.
What Symptoms Appear If the Moro Reflex Is Retained?
If, however, the Moro reflex persists beyond this integration window, it may signal that the reflex has not fully resolved—what clinicians call a “retained” reflex. Monitoring the timeline and development of this reflex, therefore, is an important part of early pediatric assessment for occupational therapists, pediatricians, and parents alike.
Most infants move on from the Moro reflex as designed. But sometimes, this reflex becomes retained, continuing to affect children well past the typical integration period. Instead of looking like a baby’s startle, a retained Moro reflex manifests in different ways in older children and adults. The following symptoms suggest a retained Moro reflex:
Anxiety and Heightened Stress Response
If an older child experiences chronic anxiety across a variety of routines and environments, this may be a sign that the Moro reflex is still present. Children with a retained Moro reflex can feel on edge, hypersensitive to stimuli, and constantly ready for “fight or flight,” a state not appropriate for day-to-day life outside the context of real danger.
Emotional Regulation Difficulties
A second marker is difficulty with emotional regulation. Children may seem emotionally “hot and cold,” swinging quickly between moods and struggling to maintain a calm emotional state. The reflex’s original purpose—to jolt the baby into alertness in response to sudden change—means that if it persists, the child may be perpetually on alert, unable to settle or self-soothe easily. This emotional turbulence can affect relationships, learning, and general well-being.
Motion Sickness
A pronounced tendency towards motion sickness is common in chidlren and adults with a retained Moro reflex. Those who have it often get carsick very quickly or find themselves nauseous during even mild movement activities, like riding a Ferris wheel. The underlying reason is a disconnect in how the body perceives and adjusts to changes in motion—originally triggered during the dramatic limb-extension of the Moro response.
Balance and Coordination Issues
Apraxia and dysprxia are balance and coordination challenges that often accompany a retained Moro reflex. Since the Moro reflex originally impacts the whole-body reaction to movement, its persistence can prevent the development of smooth, coordinated control required for activities that demand balance and postural stability. Postural control is often difficult, resulting in children who appear “disconnected” in their body’s movement patterns.
Other Potential Signs
Other associated issues of a retained Moro reflex include:
- Hypersensitivity to lights and sounds
- Chronic distractibility
- Trouble with attention and focus
- Difficulty in social settings
What Can Be Done for a Retained Moro Reflex?
Addressing a retained Moro reflex is both possible and beneficial, especially when individualized, functional activities are used. A knowledgeable occupational therapist will typically encourage practical approaches that engage the child in active movement and sensory experiences.
Functional Exercises for Integration
One specific activity involves the use of a therapy ball or yoga ball. The child lies on their back across the ball, then is encouraged to reach for and grab a toy—such as a bean bag or stuffed animal—before returning to a sitting position and tossing the toy to a target. The critical element here is the change in head position as the child lies back over the ball, which stimulates the vestibular system and directly engages the neurological circuits associated with the Moro reflex. This purposeful movement helps the nervous system learn to process motion in a new, mature way, encouraging the integration of the reflex.
Tips for Implementing Integration Activities
Feelings of safety and support are critical. If the child is apprehensive about going backward over the ball, or if they become noticeably fearful when their feet leave the ground, provide extra stability. Caregivers should always stabilize the child’s legs and offer support, making the exercise both a nurturing and therapeutic experience. Hesitancy or discomfort with the movement can be telling; it may indicate that the Moro reflex is significantly retained and impacting the child’s day-to-day function.
It’s important to remember that this ball activity is not a diagnostic tool but an integrative exercise. Formal assessment for retained reflexes should always be conducted in person with an experienced professional, such as an occupational therapist.
The Importance of Individualized Support
Because every child is different, there is no universal intervention. Some children may benefit from daily movement games, structured therapy sessions, or even classroom sensory breaks based on their unique needs and developmental stage. The goal is always to make integration exercises functional and fun—ensuring that the learning and neurological adaptation occur in a motivating, positive context.
Conclusion
The Moro reflex is a critical milestone in early childhood development, providing necessary protection and alertness during the newborn stage. Typically, it fades by six months as more sophisticated neurological responses take over. When it persists—becoming a retained reflex—it can lead to anxiety, emotional dysregulation, motion sickness, and coordination problems. Through thoughtful, functional activities and close observation, parents and professionals can both ease the reflex’s effects and help children reach their full potential. Advances in occupational therapy and parent education are making it easier than ever to recognize, assess, and integrate the Moro reflex, ensuring every child gets the best possible start.
About Maria Rickert Hong CHHC
Maria Rickert Hong is a Co-Founder of, and the Education and Media Director for, Documenting Hope.
She is a former sell-side Wall Street equity research analyst who covered the oil services sector at Salomon Smith Barney and Lehman Brothers under Institutional Investor #1 ranked analysts.
Later, she covered the gaming, lodging & leisure sector at Jefferies & Co. and Calyon Securities. She quit working on Wall Street when her first son was born.
Prior to working on Wall Street, she was a marketing specialist for Halliburton in New Orleans, where she also received her MBA in Finance & Strategy from Tulane University.
She is the author of the bestselling book Almost Autism: Recovering Children from Sensory Processing Disorder and the co-author of Brain Under Attack: A Resource for Parents and Caregivers of Children with PANS, PANDAS, and Autoimmune Encephalitis. She is a co-author of Reversal of Autism Symptoms among Dizygotic Twins through a Personalized Lifestyle and Environmental Modification Approach: A Case Report and Review of the Literature, J. Pers. Med. 2024, 14(6), 641.
Maria is also a Certified Holistic Health Counselor. Her work can be found on DocumentingHope.com, Healing.DocumentingHope.com, Conference.DocumentingHope.com and MariaRickertHong.com
