Newborn reflexes: what they are and why they matter

Newborn · Development · Reviewed 20 June 2026 · All articles

Your newborn arrives ready-wired. Before they can hold their head up, roll over, or reach for a toy, they already have a set of built-in responses that have been with them since before birth. These are called primitive reflexes, and they are one of the first things a paediatrician checks after delivery. Understanding what each reflex is, what triggers it, and when it fades gives parents a window into early neurological development and helps you recognise the signals that a check-up might be needed.

What newborn reflexes are and why babies have them

Primitive reflexes are automatic, involuntary movements that originate in the brainstem and spinal cord. They do not require conscious thought. They are believed to be evolutionary remnants, responses that helped our ancestors survive the vulnerable weeks after birth, whether that meant grasping a caregiver for safety, rooting for milk, or protecting the airway from obstruction.

As the higher centres of the brain (the cerebral cortex) mature and take over voluntary movement, most of these reflexes are gradually suppressed. Their disappearance at the expected time is actually a sign of healthy neurological development, not a loss. If a reflex persists too long, or if it is absent or asymmetric when it should be present, that is the signal that warrants attention.

Reflexes are checked at the newborn physical examination (usually within 72 hours of birth), at developmental reviews, and by your health visitor or paediatrician if you raise a concern. Knowing what each one looks like puts you in a much better position to describe what you are observing.

Quick-reference table

Rooting reflex

What it is: When something touches the corner of a newborn's mouth or cheek, the baby turns their head toward the touch and opens their mouth, as if searching for something to latch on to.

What triggers it: A light touch or stroke on the cheek, the corner of the mouth, or the upper or lower lip.

Developmental purpose: The rooting reflex is a feeding reflex. It guides the baby toward the breast or bottle, making the early mechanics of breastfeeding possible even before the baby has any experience of the world. Without it, newborns would have to learn entirely from scratch how to find the nipple.

When it fades: The rooting reflex is typically present from birth and begins to be replaced by voluntary head-turning and deliberate searching around three to four months, as the baby develops enough visual and motor control to locate a feed intentionally.

Sucking reflex

What it is: When an object touches the roof of a newborn's mouth, the baby begins rhythmic sucking movements automatically.

What triggers it: Contact with the palate, most commonly by a nipple, teat, or finger placed gently in the mouth.

Developmental purpose: The sucking reflex works in tandem with rooting. Rooting brings the baby to the nipple; the sucking reflex drives the mechanics of feeding once latch is achieved. Together, these two reflexes are essential for survival. Premature babies can have a weak or poorly coordinated sucking reflex, which is one of the reasons they sometimes need supplementary feeding support in the early weeks.

When it fades: The sucking reflex transitions to voluntary, learned sucking at around two to four months. Babies continue to suck for comfort and feeding long after the reflex component fades, but the response becomes intentional rather than automatic.

Moro (startle) reflex

What it is: The Moro reflex is often described as the most dramatic of the newborn reflexes. When a baby feels that they are falling, or when they are startled by a sudden loud sound or movement, they throw both arms out wide with fingers spread, arch their back, then draw the arms back in toward the chest, often with a brief cry.

What triggers it: The sensation of being dropped or losing support (even a few centimetres), a sudden loud noise, a sudden bright light, or an abrupt movement of the baby's head.

Developmental purpose: The Moro reflex is thought to be an ancient protective response: an infant primate losing its grip on its mother would throw its arms wide to catch her. The cry that often accompanies it may serve to alert the caregiver.

When it fades: The Moro reflex is usually present from birth and fades between four and six months. It is one of the reflexes that can disrupt newborn sleep, as babies sometimes startle themselves awake. Swaddling can reduce this disruption in the early weeks by limiting the arm movement that triggers the full response.

What to watch for: The Moro reflex should be symmetric. If only one arm responds, or if the response on one side is noticeably weaker, this can indicate a birth injury to the brachial plexus (the nerve network supplying the arm) or an injury on one side of the brain, and should be assessed by a doctor.

Palmar grasp reflex

What it is: When you place a finger in the palm of a newborn's hand and apply light pressure, the baby's fingers curl around yours and grip. The grip can be surprisingly strong: some babies can briefly support their own weight this way, though this is never a safe test to perform.

What triggers it: Pressure or touch on the palm of the hand.

Developmental purpose: Like the Moro reflex, the palmar grasp is thought to have primate origins. A baby clinging to a caregiver's body gains both warmth and safety. The reflex also begins the sensory experience of the hands that will eventually support voluntary reaching and grasping.

When it fades: The palmar grasp reflex fades between five and six months, as the cortex develops voluntary control over hand opening and closing. The plantar (foot) grasp reflex, which works in the same way when the ball of the foot is touched, persists a little longer, until around nine to twelve months.

Stepping (walking) reflex

What it is: When a newborn is held upright with their feet touching a flat surface, they make stepping movements that look remarkably like walking, lifting one foot then the other in an alternating pattern.

What triggers it: The pressure of a flat surface against the soles of the feet, combined with the upright position.

Developmental purpose: The stepping reflex does not directly relate to walking. It is controlled by circuits in the lower brainstem and spinal cord rather than the higher brain regions that coordinate true locomotion. Its purpose is not fully understood, but it may prime the neural circuits that will eventually be recruited for walking, months later.

When it fades: The stepping reflex usually disappears by around two months. It is sometimes temporarily suppressed in babies who gain weight quickly, as the legs become relatively heavier. True walking, which requires balance, strength, coordination, and higher-brain involvement, typically emerges between nine and fifteen months.

Tonic neck (fencing) reflex

What it is: When a baby lying on their back has their head turned to one side, the arm and leg on the side the face is pointing toward extend outward, while the arm and leg on the other side flex inward. The overall position resembles a fencer's stance, which is why this reflex is sometimes called the fencing reflex.

What triggers it: Turning the baby's head to either side while they are lying on their back.

Developmental purpose: The tonic neck reflex is thought to help coordinate early eye-hand awareness: as the baby looks toward the extended arm, it begins to connect the visual system with the sensation of the limb. It may also be involved in the early preference for looking to one side, which eventually gives way to more symmetric visual attention.

When it fades: The tonic neck reflex is typically present from birth and fades by five to seven months. Its presence can be variable: not every head turn will produce the full classic response in every newborn.

Babinski reflex

What it is: When the outer edge of the sole of the foot is stroked from heel to toe, the big toe fans upward while the other toes spread out. In older children and adults, the same stroke produces the opposite response: the toes curl downward.

What triggers it: A firm stroke along the outer edge of the sole, from the heel toward the little toe.

Developmental purpose: The Babinski reflex reflects the immaturity of the corticospinal tract, the pathway that carries voluntary motor signals from the brain down the spinal cord. In newborns this tract is not yet fully myelinated (insulated), so the response is uninhibited. As myelination completes, usually over the first one to two years of life, the response becomes suppressed and the adult pattern appears.

When it fades: The upgoing Babinski response is normal in babies and toddlers until around twelve to twenty-four months. After that point, an upgoing Babinski in a child or adult is a clinical sign of upper motor neuron damage and prompts neurological investigation.

What a missing or asymmetric reflex can signal

During the newborn physical examination, the paediatrician or midwife checks the major reflexes systematically. An absent, weak, or asymmetric reflex is not automatically a diagnosis of anything serious, but it is always followed up. Here is what different presentations can indicate.

• Absent Moro on one side: can suggest a brachial plexus injury (Erb's palsy) from a difficult delivery, a fractured clavicle, or a brain lesion on the opposite side. This is one of the most clinically important asymmetric findings.
• Absent or very weak sucking reflex: common in premature babies due to immaturity, but in full-term babies can indicate neurological depression (from birth asphyxia, medication, or infection), a problem with the cranial nerves involved in sucking, or significant illness.
• Absent rooting with absent sucking: if both feeding reflexes are absent or markedly depressed in a full-term baby, this usually prompts investigation for a neurological cause.
• Asymmetric palmar grasp: raises the question of a unilateral problem with the nerve supply to that arm or hand.
• Persistent reflexes beyond their expected window: a reflex that has not faded by the age at which it should be gone can be a sign of delayed neurological maturation or cerebral palsy, particularly when accompanied by other developmental concerns.

None of these findings is a diagnosis in itself. A thorough clinical assessment, and sometimes imaging or specialist review, is needed to understand what is happening. What matters is that the finding is noticed, which is exactly why reflexes are checked systematically rather than left to chance observation.

Why parents should be familiar with these reflexes

You will encounter these reflexes in your daily life with a newborn without necessarily recognising them. The rooting and sucking reflexes shape every feed. The Moro reflex wakes your baby when you lower them into the cot. The palmar grasp gives you that first extraordinary moment of your finger being held.

Knowing what is happening in these moments has a practical benefit: if you notice something that does not look right, that one arm is not moving as freely as the other, that your baby does not seem to turn toward touch the way the books describe, or that a reflex seems to still be strongly present at six months, you have a specific observation to share with your health visitor or doctor. Specific observations lead to faster assessments than vague concern.

Reflexes are also a reminder of how much work your baby's brain is doing in the weeks and months after birth. Each reflex that fades represents a step toward voluntary, intentional movement: from a baby who grips by reflex to one who reaches out deliberately; from a baby who steps without knowing it to one who walks across the room to you. The journey from reflex to intention is one of the most remarkable things you will watch unfold.

Frequently asked questions

When do newborn reflexes disappear?

Most primitive newborn reflexes fade between two and six months as the brain matures and voluntary control develops. The rooting and sucking reflexes tend to last the longest, often persisting until around four months. The Moro reflex typically disappears by four to six months, and the palmar grasp reflex by five to six months.

What does it mean if a newborn reflex is missing?

A missing or asymmetric reflex can indicate a problem with the nervous system, a birth injury such as a brachial plexus injury, or muscle weakness on one side. It does not always mean something serious, but it is always investigated by the paediatrician during the newborn examination and at follow-up checks.

Is the Moro reflex the same as the startle reflex?

Yes. The Moro reflex and the startle reflex are the same response. The baby extends the arms and legs, spreads the fingers, then brings the arms back toward the body, often crying briefly. It is triggered by sudden movement, sound, or the sensation of falling.

Does the stepping reflex mean my baby will walk early?

No. The stepping reflex is a primitive reflex controlled by the lower brain and spinal cord, not the higher brain centres needed for real walking. It disappears by around two months and bears no relationship to when your baby will take their first independent steps, which typically happens between nine and fifteen months.

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Sources

• American Academy of Pediatrics: Newborn reflexes
• NHS: Newborn baby checks
• MedlinePlus: Infant reflexes
• StatPearls: Primitive reflexes (NCBI)