What reflexes should be screened in a newborn with no prior medical history within the first week of life?

Newborn Reflex Screening in the First Week of Life

Screen all newborns for primitive reflexes (Moro, palmar grasp, plantar grasp, rooting, sucking, asymmetric tonic neck reflex, and Galant) and protective reflexes, as these provide critical early assessment of central nervous system integrity and predict neurodevelopmental outcomes. 1, 2

Essential Primitive Reflexes to Assess

Core Reflexes Present at Birth

• Moro reflex: Should be present and symmetric in all full-term newborns within the first week, elicited by sudden head extension or loud noise 1, 3
• Palmar grasp reflex: Present in all newborns from birth, with strong finger flexion when palm is stimulated 3, 4
• Plantar grasp reflex: Present at birth, with toe flexion when sole is stimulated 2, 3
• Rooting reflex: Should be present when cheek is stroked, causing the infant to turn toward the stimulus 5, 1
• Sucking reflex: Must be present and coordinated for feeding 5

Additional Primitive Reflexes

• Asymmetric tonic neck reflex (ATNR): Present in most newborns, though may be subtle in the first week; infant assumes "fencing position" when head is turned 1, 2
• Galant reflex (lateral trunk incurvature): Present by term, elicited by stroking the back parallel to the spine, causing lateral trunk flexion 2, 3

Brainstem and Cranial Nerve Reflexes

Critical Brainstem Reflexes

• Pupillary light reflex: Both pupils should react to bright light; pupils are typically 4-9 mm and should constrict symmetrically 5, 6
• Corneal reflex: Eyelid closure when cornea is gently touched 5, 6
• Gag and cough reflexes: Test by stimulating posterior pharynx and observing for protective response 5

Facial and Oropharyngeal Assessment

• Facial symmetry: Observe facial movements during crying and grimacing; asymmetry suggests cranial nerve dysfunction 5
• Eye movements: Assess for full range of extraocular movements and tracking ability 5, 4
• Red reflex: Must be present and symmetric bilaterally to rule out retinoblastoma and cataracts 5

Deep Tendon Reflexes

• Biceps, patellar, and Achilles reflexes: Should be present and symmetric, though may be less brisk in the immediate newborn period compared to older infants 6, 4
• Plantar response (Babinski): An extensor response (upgoing toe) is normal in newborns and does not indicate pathology at this age 6, 4

Red Flags Requiring Immediate Evaluation

Asymmetry or Absence

• Asymmetric reflexes: Any side-to-side difference in primitive reflexes, particularly Moro or grasp, suggests focal neurological injury such as brachial plexus injury or stroke 2, 4
• Absent reflexes: Complete absence of Moro, grasp, or sucking reflexes indicates significant central nervous system dysfunction 2, 3

Abnormal Tone Patterns

• Hypotonia with weak reflexes: Suggests lower motor neuron disease, neuromuscular disorder, or central hypotonic syndrome 5, 2
• Hypertonia with hyperactive reflexes: May indicate hypoxic-ischemic encephalopathy or other upper motor neuron pathology 5, 6

Examination Technique Considerations

Optimal Testing Conditions

• Examine the infant when alert and calm, ideally between feedings 7, 4
• Maintain neutral head position when testing extremity reflexes to avoid ATNR interference 2, 4
• Ensure adequate warmth (core temperature >35°C) as hypothermia dampens reflex responses 5, 7

Documentation Requirements

• Record presence, absence, or asymmetry of each reflex tested 6, 4
• Grade intensity when possible (though formal 0-4+ grading is more relevant for deep tendon reflexes in older children) 6
• Note any abnormal posturing or movement patterns 5, 2

Clinical Pitfalls to Avoid

• Do not confuse spinal reflexes with voluntary movement: Withdrawal to noxious stimuli may be spinally mediated and does not indicate intact brain function 5, 6
• Avoid testing immediately after feeding or during active crying: This reduces reliability of elicited responses 7, 4
• Do not overlook subtle asymmetries: Even mild asymmetry in primitive reflexes warrants close follow-up as it may predict cerebral palsy 2
• Remember that absence of deep tendon reflexes is more concerning than brisk reflexes in newborns: Absent reflexes suggest neuromuscular pathology, while brisk reflexes may be normal 5, 4