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 functioning. These primitive reflexes are not quirks — they are diagnostic tools, deeply interesting developmental phenomena, and in some cases genuinely functional responses that served survival purposes long before modern medicine existed.
For parents, understanding what these reflexes are and what triggers them turns puzzling newborn behaviours into recognisable patterns. The rooting response that causes a baby to turn toward anything touching their cheek is not randomness — it is a feeding-seeking behaviour present from birth. The Moro reflex that causes a baby to throw their arms wide in response to a sudden movement is the neurological equivalent of a grab reflex that would have helped an infant cling to their mother in a less domestically comfortable evolutionary context.
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
The rooting reflex is the foundational feeding reflex. When the corner of a newborn's mouth or cheek is stroked, the baby turns their head in that direction and opens their mouth. This response is what allows a baby who is placed skin-to-skin after birth to find the nipple without guidance, and it remains active for feeding throughout the early weeks. The rooting reflex is typically present from birth and fades from around three to four months as feeding becomes voluntary and directed.
The Sucking Reflex
Closely paired with rooting is the sucking reflex — the automatic, rhythmic sucking motion triggered by anything placed in contact with the roof of the mouth. This reflex is present and coordinated from around 36 weeks of gestation, which is one of the reasons premature babies born before this point may need feeding support. The sucking reflex integrates with voluntary feeding behaviour gradually over the first months and does not simply disappear — it transitions into a voluntary skill.
The Moro Reflex
The Moro reflex is the most dramatic of the newborn reflexes and often the most startling for parents to witness. When a baby experiences a sudden change in position — their head drops back unexpectedly, or there is a sudden loud noise — they respond by throwing both arms outward with hands open, then drawing them back toward the body, often with a cry. The whole sequence takes about two seconds.
The Moro is present from birth and is usually most noticeable in the early weeks. It begins to fade from around three months and should be largely absent by five to six months. Asymmetry — where one arm responds but not the other, or where one arm responds more weakly — can indicate injury to the brachial plexus (the nerve network supplying the arm) or a fracture of the clavicle that sometimes occurs during a difficult delivery, both of which are usually identified before discharge from the maternity unit.
The Palmar Grasp
Place a finger in the palm of a newborn's hand and they will close their fingers around it with surprising strength. This palmar grasp reflex is present from birth and is one of the most universally delightful discoveries for new parents. It is involuntary — the baby is not choosing to hold on — and it disappears from around three to four months as the brain begins developing voluntary hand opening and deliberate reaching. The voluntary grasp that replaces it, which emerges from around four to five months, is meaningfully different: the hand opens intentionally before contact, and the fingers close 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 will curl downward. This plantar grasp reflex fades from around eight to twelve months, which is relevant timing because it needs to have resolved before weight-bearing and walking become comfortable.
The Stepping Reflex
Hold a newborn upright with the soles of their feet touching a firm surface and they will 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 is a primitive spinal-cord-level response, whereas voluntary walking requires far more complex cortical development. Parents who discover this reflex sometimes worry when it disappears, but its fading is a sign of normal neurological progression, not a loss.
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 — the so-called "fencer position." This ATNR is present from birth and fades from around four to six months. While it is present, it helps develop hand-eye coordination by bringing the extended hand into the baby's visual field. Its persistence beyond six months is considered atypical and worth mentioning to a paediatrician.
What Absent or Asymmetric Reflexes Mean
The routine newborn examination specifically checks these reflexes because their presence, symmetry, and 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 does not — are always worth investigating regardless of cause, as they can indicate localised injury or underlying structural differences.
If your paediatrician mentions an absent or unusual reflex at a routine check, the appropriate response is the follow-up they recommend rather than alarm. Most findings at this level resolve or prove benign with observation, and early identification of anything that does not is the whole point of the check.
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.
