Within hours of birth, a healthy newborn demonstrates a set of involuntary, automatic movements that have been present since before birth and that reveal a great deal about how the nervous system is working. These primitive reflexes are not quirks — they are diagnostic tools, and in some cases genuinely functional responses that served survival purposes long before modern medicine.
For parents, understanding these reflexes turns puzzling newborn behaviours into recognisable patterns. The rooting response — a baby turning toward anything touching their cheek — is a feeding-seeking behaviour present from birth, not a random movement. The Moro reflex — arms flinging wide in response to sudden movement — is the neurological equivalent of a grasping response that, in our evolutionary past, would have helped an infant cling to their mother.
This article covers the main reflexes your paediatrician will check, what they look like, when they appear and disappear, and what their absence or asymmetry might mean. If you want to track when specific reflexes fade and new voluntary skills take their place, the Healthbooq app includes a developmental milestone tracker built around these early windows.
The Rooting Reflex
Stroke the corner of a newborn's mouth or cheek and they'll turn their head in that direction and open their mouth. This is the rooting reflex — the foundational feeding reflex. It's what allows a baby placed skin-to-skin after birth to locate the nipple without guidance, guided purely by touch. It remains active through the early weeks of feeding and fades from around three to four months as feeding becomes voluntary and directed.
Parents often notice rooting when a baby's cheek brushes against a shoulder or arm and the baby turns toward it eagerly, mouth open. This is worth knowing: it means the reflex can be accidentally triggered, and a baby nuzzling against you isn't necessarily hungry.
The Sucking Reflex
Closely linked to rooting, the sucking reflex is the automatic, rhythmic sucking motion that's triggered by anything placed in contact with the roof of the mouth. It's present and coordinated from around 36 weeks of gestation — which is why premature babies born before this point often need feeding support and may not be able to breastfeed or bottle-feed directly. Between 34 and 36 weeks, infants may have a weak, disorganised suck that tires easily.
The sucking reflex transitions gradually into voluntary, skilled feeding behaviour over the first months. It doesn't simply disappear — it evolves.
The Moro Reflex
The Moro reflex is the most dramatic newborn reflex, and consistently startles parents who don't know to expect it. When a baby experiences a sudden change in position — their head drops back unexpectedly, or there's a sudden loud noise — they respond by throwing both arms outward with hands open, then drawing them back toward the body, often accompanied by a cry. The entire sequence takes about two seconds.
The Moro is present from birth, often most noticeable in the early weeks, and fades from around three months. It should be largely absent by five to six months.
What asymmetry means: one arm responding but not the other, or one arm responding more weakly, can indicate injury to the brachial plexus (the nerve network supplying the arm) or a clavicle fracture from a difficult delivery. Both are usually identified before discharge from the maternity unit, but asymmetric Moro is the most common reason a neonatologist looks more carefully at a shoulder during the newborn examination.
The Palmar Grasp
Place a finger in the palm of a newborn's hand and they'll close their fingers around it with surprising firmness. This palmar grasp reflex is present from birth and is one of the universally delightful discoveries for new parents — it feels intentional, but it isn't. The baby isn't choosing to hold on.
The reflex disappears from around three to four months as the brain develops voluntary hand opening and deliberate reaching. The voluntary grasp that replaces it — emerging from around four to five months — is meaningfully different: the hand opens before contact, fingers spread in anticipation, and the grip closes with purposeful intent.
The Plantar Grasp
The same curling response occurs in the feet: stroke the sole of a newborn's foot and the toes curl downward. This plantar grasp reflex fades from around eight to twelve months. The timing matters because it needs to have resolved before weight-bearing and walking become comfortable — the toe-curling response would interfere with a flat foot landing on the ground.
The Stepping Reflex
Hold a newborn upright with the soles of their feet touching a firm surface and they'll make stepping movements, alternating each foot as if walking. This reflex is present from birth and disappears at around two months. It has no direct relationship to later walking ability; it's a primitive spinal-cord-level response. Voluntary walking requires far more complex cortical development and won't emerge for another year.
Parents who discover this reflex sometimes worry when it disappears. Its fading is a sign of normal neurological progression — the primitive spinal response is being superseded by more sophisticated cortical control.
The Asymmetric Tonic Neck Reflex (ATNR)
When a newborn's head is turned to one side while they lie on their back, the arm on the face side extends while the opposite arm bends — sometimes called the "fencer position." The ATNR is present from birth and fades from around four to six months. While present, it helps develop hand-eye coordination by bringing the extended hand into the baby's line of sight. Persistence beyond six months — a position the baby can't break out of voluntarily — is worth mentioning to a paediatrician.
What Absent or Asymmetric Reflexes Mean
The routine newborn examination checks these reflexes specifically because their presence, symmetry, and age-appropriate development are reliable indicators of neurological health.
Absent reflexes can indicate: immaturity (particularly relevant in premature babies), neurological injury, or neuromuscular conditions. Asymmetric reflexes — where one side responds and the other doesn't — always warrant investigation, as they can point to localised injury or structural differences.
The appropriate response to a paediatrician mentioning an absent or unusual reflex at a routine check is to follow whatever follow-up they recommend rather than search online for worst-case scenarios. Most findings at this level resolve or prove benign with observation. Early identification of anything that doesn't resolve — which is the whole point of the newborn examination — allows for earlier intervention.
Key Takeaways
Newborn reflexes are involuntary movements that indicate a healthy, functioning nervous system. The most important ones include the rooting, sucking, Moro (startle), palmar grasp, plantar grasp, and stepping reflexes. Most primitive reflexes disappear between two and six months as the brain develops voluntary control. A neurologist or paediatrician checks these reflexes at routine newborn assessments. Absent or asymmetric reflexes can indicate neurological issues that benefit from early identification, which is why these checks matter.
