Newborn Reflexes

A newborn who doesn't root or grasp may look "sleepy" — but absent or asymmetric reflexes can signal neurological injury that demands immediate escalation.

Newborn reflexes are involuntary motor responses mediated by the brainstem and spinal cord. Their presence confirms neurological integrity; their absence or asymmetry suggests CNS damage, birth trauma, or peripheral nerve injury. The highest-yield reflexes for NCLEX are: Moro (startle) — elicited by sudden head extension, produces symmetric arm abduction with finger spreading followed by adduction in an "embrace"; disappears by 4–6 months. Rooting — stroking the cheek causes the newborn to turn toward the stimulus; disappears by 3–4 months. Sucking — triggered by placing a finger or nipple in the mouth; present by 32 weeks gestation, coordinates with swallowing by 34 weeks. Palmar grasp — firm finger pressure on the palm produces flexion; disappears by 3–4 months. Babinski — stroking the lateral sole produces dorsiflexion of the great toe with fanning of other toes; this is normal in newborns and disappears by 12–24 months. Tonic neck (fencing) — turning the head to one side extends the arm and leg on that side while flexing the opposite limbs; disappears by 3–4 months. Asymmetric Moro suggests fractured clavicle or brachial plexus injury (Erb palsy). Absent sucking or rooting in a term newborn warrants neurological evaluation.

Key Distinctions

Don't confuse a normal newborn Babinski (toes fan and dorsiflex) with the abnormal adult Babinski — same response, different meaning based on age. Students mix up rooting and sucking: rooting is the search behavior (turns head), sucking is the feeding action (rhythmic compression). An asymmetric Moro is more clinically significant than a weak but symmetric Moro — asymmetry points to a specific unilateral injury.

Clinical Pearl

Moro should be a mirror — both arms out, both arms in. If one arm stays still, think clavicle fracture or Erb palsy and report immediately.