Innate neonatal reflexes: indicators of neurological maturation and developmental strategies

Neonatal reflexes are automatic, stereotyped motor responses present from birth, essential for immediate survival, feeding, protection, and the newborn’s neurobehavioral development. These involuntary responses are not simple isolated movements, but integrated components of a highly evolved biological system that supports the newborn’s adaptation to the extrauterine environment. Observing and assessing them provides valuable information about neurological maturity and central nervous system functioning, giving caregivers tools to interpret the infant’s signals and respond appropriately to their needs.

From a neurophysiological standpoint, neonatal reflexes are mediated by spinal and brainstem circuits, with limited cortical contributions in the first weeks of life. Integration between sensory stimuli (tactile, visual, olfactory) and motor responses enables the newborn to orient toward sources of nourishment, maintain postural stability, explore the environment, and communicate basic needs. Limbic circuits and neuroendocrine systems—including oxytocin and dopamine—modulate the newborn’s behavioral response and promote synchronization with the caregiver, facilitating early attachment and reciprocal emotional regulation.

Functionally, neonatal reflexes have multiple adaptive roles:

• For the newborn: they ensure feeding (such as the rooting and sucking reflexes), protection from sudden stimuli (Moro reflex), exploration and contact with the environment and mother (grasping reflex, postural movements).
• For the caregiver: these reflexes provide clear signals about alertness, hunger, stress, or well-being, guiding caregiving, protection, and interaction.

In this sense, neonatal reflexes constitute a primary biological language between newborn and caregiver, essential for building an early emotional bond and supporting psychomotor development. Understanding the neurological bases and adaptive functions of neonatal reflexes not only allows correct interpretation of newborn behavior, but also forms a foundation for clinical practice in neonatology and pediatrics, aimed at optimizing feeding, safety, neurological development, and the mother–infant bond.

Classification of neonatal reflexes

The classification of neonatal reflexes stems from neurological studies in the early decades of the 20th century, with contributions from researchers such as Joseph Babinski, Ernst Moro, Jules Landau, and Johannes Galant, who described reflexes fundamental to survival, muscle tone, and newborn protection. In the 1960s and 1970s, authors such as Prechtl and Brazelton formalized a modern classification based on adaptive function and neurological control. Neonatal reflexes are generally divided into three main categories according to their adaptive function and neurological control: primitive reflexes, postural reflexes, and automatic locomotion reflexes. This subdivision helps clarify the different evolutionary purposes of reflexes and allows systematic evaluation of neurological development.

 

1. Primitive reflexes

Primitive reflexes are automatic responses present at birth and, on average, integrated or suppressed within the first months of life. They serve primarily survival and feeding, enabling the newborn to obtain food, protection, and contact with the caregiver.

Rooting reflex: this appears when a tactile stimulus is applied to the newborn’s cheek or to the sides of the mouth. In response, the newborn turns the head toward the stimulus, opens the mouth, and orients lips and tongue toward the nipple or food source. This reflex is crucial in the first days of life to facilitate latching and ensure effective feeding without external intervention.

• Neurophysiological basis: mediated by brainstem circuits and cranial motor nuclei (V and VII), integrating cutaneous and proprioceptive sensory input.
• Timing: present immediately at birth; disappears around 4 months.
• Clinical relevance: absence or weakness may indicate hypotonia, cranial injury, or neurological delay; its presence and strength are monitored to assess basic neurological integrity.

Sucking reflex: this involves rhythmic sucking in response to stimulation of the palate, lips, or cheek, enabling the newborn to extract milk. It is essential for early nutrition, stimulation of maternal milk production via oxytocin, and regulation of hunger and satiety.

• Neurophysiological basis: controlled by brainstem motor nuclei (mainly the trigeminal and facial nerve nuclei), connected with sensory structures and emerging corticospinal pathways.
• Timing: present at birth; normally integrated by 4 months when sucking becomes voluntary.
• Clinical relevance: difficulty with the sucking reflex can compromise breastfeeding and may signal hypotonia, prematurity, or neurological injury.

Moro reflex: triggered by sudden stimuli such as a change in position or a loud noise. The newborn extends and abducts arms and legs, then brings them back toward the trunk in an “embracing” motion. Its main function is protective, preparing the newborn to react to potential threats.

• Neurophysiological basis: mediated by brainstem circuits, particularly the superior colliculus and vestibular nuclei, with sensory integration from the labyrinth and muscle receptors.
• Timing: present at birth; generally disappears between 3 and 6 months.
• Clinical relevance: absence, asymmetry, or persistence beyond 6 months may indicate neurological damage, brachial plexus palsy, or central nervous system disorders.

 

Grasping reflex: the grasping reflex appears when the palm of the hand or the sole of the foot is stimulated: the newborn closes the fingers/toes around the object or surface. This reflex promotes early tactile contact, stimulates exploration, and strengthens the mother–infant relationship through physical contact.

• Neurophysiological basis: a spinal reflex mediated by α and γ motor neurons, with cutaneous and proprioceptive sensory integration.
• Timing: appears immediately at birth; disappears between 3 and 4 months.
• Clinical relevance: absence may indicate peripheral nerve or spinal lesions; persistence beyond the typical period may suggest neuromotor dysfunction.

 

2. Postural reflexes

Postural reflexes emerge in the first months of life and reflect maturation of motor control, posture, and balance. They anticipate the development of complex, coordinated voluntary movements.

Galant reflex: observed by stimulating laterally the newborn’s lumbar region along the spine. The typical response is lateral trunk flexion toward the stimulus, sometimes accompanied by a slight movement of the lower limbs.

• Adaptive function: facilitates postural adjustment movements and contributes to early motor development, such as rolling and stabilizing in the prone position.
• Neurophysiological basis: mediated by spinal circuits and interneurons within the spinal cord, integrating tactile and proprioceptive input.
• Timing: present at birth; generally disappears between 4 and 6 months.
• Clinical relevance: absence may indicate spinal cord lesions or hypotonia; excessive or asymmetric response may suggest neuromotor abnormalities.

 

Babinski reflex: elicited by stroking the sole of the newborn’s foot from the lateral heel toward the toes. The response is dorsiflexion (upward extension) of the toes with abduction.

• Adaptive function: reflects maturation of pyramidal pathways and the functioning of spinal and corticospinal systems. In newborns, toe dorsiflexion is normal; the same response in adults may indicate neurological lesions.
• Neurophysiological basis: depends on the integrity of corticospinal motor neurons and spinal circuits, with sensory modulation from plantar stimulation.
• Timing: present at birth; generally disappears between 6 and 12 months as cortical reflexes mature.
• Clinical relevance: absence in a newborn may indicate peripheral neuropathies or spinal lesions; persistence beyond the expected period may suggest corticospinal tract injury.

 

Landau reflex: observed by lifting the infant in a prone position while supporting the chest and leaving the limbs free. The infant responds with simultaneous extension of the head, trunk, and limbs, as if trying to maintain balance.

• Adaptive function: anticipates development of postural control and trunk muscle strength, both fundamental for future walking and maintaining an upright posture.
• Neurophysiological basis: mediated by brainstem and spinal circuits integrating vestibular and proprioceptive information, with tonic muscular modulation.
• Timing: appears around 3 months; peaks in intensity between 3 and 12 months; gradually fades as voluntary movement control and posture stabilize.
• Clinical relevance: absence may indicate generalized hypotonia or neuromotor delay; weak or incomplete response may reflect central or peripheral neurological deficits.

 

3. Automatic locomotion reflexes

Automatic locomotion reflexes are innate motor patterns that allow the newborn to perform coordinated movements in response to specific stimuli, without voluntary control. These reflexes anticipate complex motor patterns such as walking and swimming, and provide a foundational basis for the development of voluntary mobility and more sophisticated motor coordination. They reflect the integrity of spinal and brainstem circuits and contribute to early motor learning.

Automatic stepping reflex: when the newborn is held upright with the feet touching a flat surface, alternating lower-limb movements resembling steps appear. This behavior is considered a motor predisposition that anticipates voluntary walking, supporting limb–trunk coordination and modulation of lower-limb muscle tone.

• Timing: present at birth; typically disappears within 6–8 weeks due to increased body weight limiting spontaneous movement.
• Adaptive function: contributes to development of locomotor patterns and helps assess the neuromotor integrity of spinal circuits.

Swimming reflex: when the newborn is partially immersed in water, coordinated arm and leg movements appear, with automatic breathing, resembling floating and swimming patterns. This reflex indicates basic neuromotor coordination, balance, and sensory integration.

• Timing: present at birth; normally decreases within 4–6 months as voluntary movement control begins to prevail.
• Adaptive function: promotes balance and movement patterns in an aquatic environment, stimulates muscles and joints, and contributes to later voluntary mobility.

 

Guidelines for assessing neonatal reflexes

Guidelines for assessing neonatal reflexes are evidence-based clinical recommendations that define methods, timing, and criteria for observing innate reflexes in newborns. These protocols help standardize early neurological examinations, correctly interpret reflex responses, identify potential neuromotor developmental abnormalities early, and guide timely clinical interventions. The main goal is to ensure a reliable and reproducible evaluation of neonatal reflexes, promoting monitoring of neurological maturity, newborn safety, and the quality of clinical care.

1. Examination setting

• • The neonatal neurological exam should be conducted in a calm, warm environment and during a state of quiet alertness (“quiet alert”) to minimize factors that alter reflex responses.
  • Before assessing reflexes, it is appropriate to observe muscle tone (axial and peripheral), baseline posture, and spontaneous movements to provide a complete picture of neurological maturity.

2. Reflexes to evaluate

• • Major primitive reflexes such as Moro, sucking, rooting, and palmar grasp should be tested, as indicated in the standard neonatal neurological examination.
  • Spinal and postural reflexes (e.g., the Galant reflex) should also be included in the neurological assessment.
  • In high-risk newborns (e.g., preterm infants, those with hypotonia or critical conditions), more frequent monitoring of primitive reflexes is recommended, since absent or abnormal responses may predict unfavorable neurological development.

3. Interpretation of responses

• • Presence, intensity, symmetry, and persistence of reflexes should be interpreted in light of the newborn’s gestational age. Neurological maturation influences these parameters.
  • Absence or asymmetry of a reflex that should be present, or persistence beyond the expected period, are signs requiring further neurological assessment.
  • Physiological variability should be considered: in healthy newborns, the strength or presence of some reflexes may vary in the first days of life.

4. Monitoring over time

• • Repeat the neurological examination, including reflexes, at regular intervals (e.g., during pediatric check-ups) to assess reflex integration or evolution.
  • Clearly document each reflex response: timing pattern, presence/absence, symmetry, strength. This helps highlight changes over time and guide any investigations.
  • In situations of neurological risk (newborns with encephalopathy, hypotonia, perinatal complications), use neurobehavioral scales or more sophisticated neurofunctional exams (e.g., Neurofunctional Assessment) to complement reflex assessment.

5. Clinical intervention and follow-up

• • If reflex responses are abnormal, schedule a specialist neurological evaluation (pediatric neurologist) and consider imaging or electrophysiological tests if indicated.
  • Activate early intervention pathways (physiotherapy, motor stimulation) in newborns with reflex alterations suggestive of neuromotor dysfunction.
  • Train healthcare staff (midwives, pediatricians) on correct methods for eliciting reflexes and on the clinical implications of abnormal responses to ensure a reliable and consistent examination.

6. Documentation and quality of the exam

• • Use standardized protocols for the neonatal neurological exam, including reflexes, such as those described in the NIPE (Newborn and Infant Physical Examination) guidelines.
  • Ensure regular training for practitioners on reflex identification and clinical standards to improve diagnostic accuracy and reduce inter-operator variability.
  • Record and analyze reflex data in clinical databases to support ongoing study of normal variability in neonatal reflexes and improve evidence-based practice.

 

Dividing neonatal reflexes into primitive, postural, and automatic locomotion categories provides a key conceptual framework for understanding and interpreting the many adaptive functions these innate behaviors serve.

Through this classification, it becomes clear how each reflex contributes to the newborn’s survival, postural maintenance, and development of future voluntary motor patterns, highlighting their evolutionary and biological relevance. Moreover, systematic evaluation of reflexes enables estimation of neurological maturity: absence, persistence beyond expected timelines, or asymmetry in responses may represent early signs of neurological dysfunction or impaired motor development.

This classification therefore provides useful tools for healthcare professionals to guide targeted early clinical interventions, promptly identifying possible delays in neuromotor development or disorders of tone and coordination and enabling implementation of specific stimulation and functional support protocols aimed at promoting harmonious maturation of the central and peripheral nervous systems. In this way, knowledge and application of neonatal reflex classification function not only as a diagnostic observation method, but also as a guide for preventive strategies and for promoting physiological and motor development in the newborn.