Every parent witnesses the Moro reflex in the first weeks – that full-body startle, arms flinging out, when the baby is moved suddenly or startled by a sound. It looks alarming. Understanding it as a reflex rather than a sign of distress changes the experience completely.
Newborn reflexes are not quirks or accidents. They are hard-wired, neurologically meaningful responses that have evolutionary functions and clinical significance. A baby who lacks expected reflexes, or whose reflexes persist beyond the age at which they should have integrated, is providing the clinical team with important information about their nervous system. Knowing the main reflexes and their normal timelines helps parents notice what's typical and what warrants a check.
Healthbooq (healthbooq.com/apps/healthbooq-kids) covers newborn development and the first weeks.
Why Primitive Reflexes Exist
Primitive reflexes arise from the brainstem and spinal cord – the phylogenetically ancient parts of the nervous system – and do not require cortical involvement. They are present from birth and serve several functions: some facilitate feeding (rooting, sucking), some protect against threat (Moro, asymmetric tonic neck), and some may facilitate birth (stepping).
As the cortex develops and higher brain functions mature, the cortex inhibits these reflexes and they "integrate" – they do not disappear entirely, but they become inaccessible as automatic responses. If the cortex fails to develop properly (as in cerebral palsy or other neurological conditions), primitive reflexes may persist or re-emerge.
Sally Goddard Blythe at the Institute for Neuro-Physiological Psychology (INPP) in Chester has written extensively on the developmental significance of primitive reflex integration and its relationship to learning difficulties when integration is incomplete or delayed. This area remains somewhat outside mainstream clinical practice but is influential in educational neuroscience.
The Key Reflexes
Moro reflex (startle reflex): Elicited by a sudden change in head position, a loud noise, or a sensation of falling. The response is a bilateral extension and abduction of the arms, followed by drawing the arms back to the midline with a cry. Present from birth; integrates between 3 and 6 months. Absence of the Moro at birth may indicate birth asphyxia or central nervous system depression. Persistence beyond 6 months is associated with hypersensitivity to sensory stimulation and anxiety. An asymmetric Moro (one arm responds differently from the other) raises concern about brachial plexus injury (Erb's palsy) or neurological asymmetry.
Rooting reflex: Touch the cheek or corner of the mouth and the baby turns toward the stimulus and opens their mouth. Present from birth; integrates at 3-4 months. Facilitates breastfeeding by directing the baby toward the nipple. Many parents notice this reflex when holding their baby against their chest and the baby turns and begins rooting against their shoulder.
Sucking reflex: Elicited by placing a finger or nipple on the baby's palate. Coordinates with rooting. Present from around 32 weeks gestation; integrates at 3-4 months as feeding becomes more voluntary. Absence or weakness in a newborn suggests prematurity or neurological difficulty and affects feeding ability.
Palmar grasp reflex: Stroking the palm of the hand causes the fingers to curl tightly around whatever is touching them. A newborn grasped this way can be quite difficult to release. Present from birth; integrates at 4-6 months, making way for voluntary purposeful grasping. Persistence beyond 6 months is associated with difficulty developing pincer grip and fine motor skills.
Plantar grasp reflex: Pressing on the ball of the foot causes the toes to curl downward. Present from birth; integrates at around 12 months to allow standing and walking. Persistence beyond 18 months raises concern.
Babinski reflex: Stroking the outer edge of the sole of the foot from heel to toe causes the big toe to extend upward (dorsiflexion) and the other toes to fan out. This is normal in babies and young children up to about 12-18 months. In adults and older children, an upgoing Babinski (positive Babinski sign) indicates an upper motor neuron lesion. In a baby, it is an expected finding.
Stepping/walking reflex: Holding a baby upright with their feet touching a firm surface causes them to make stepping movements. Present from birth; integrates at 2-3 months, reappearing as voluntary walking at 9-12 months.
Asymmetric tonic neck reflex (ATNR): When a baby's head is turned to one side, the arm and leg on that side extend while the opposite limbs flex (the "fencing posture"). Present from birth to 6 months; should integrate by 6 months. Persistence beyond 6 months interferes with rolling, crawling, and later reading and writing, because it links head position to limb position in a way that interferes with crossing the midline.
What the Newborn Examination Checks
The newborn physical examination (NIPE) performed in the first 72 hours and again at 6-8 weeks includes an assessment of tone, reflexes, and neurological status. The examining clinician checks for the presence and symmetry of key reflexes, tone (resistance to movement), and any abnormal movements. Parents who have a concern about their baby's tone or responses should raise it at the examination, and the NIPE screen can be repeated if concerns arise.
Key Takeaways
Newborn reflexes (also called primitive or neonatal reflexes) are automatic, involuntary responses to specific stimuli that are present from birth and reflect normal brainstem and spinal cord function. They are assessed by midwives and paediatricians as part of the newborn examination and provide valuable information about neurological health. Most primitive reflexes disappear (integrate) in the first months of life as the developing cortex takes over voluntary control. Persistence of primitive reflexes beyond expected ages is associated with developmental difficulties. The Moro reflex, rooting reflex, grasp reflex, and sucking reflex are among the most clinically and parentally significant.
