Newborn Reflexes: Guide to Baby's Primitive Reflexes

What Are Newborn Reflexes?

Newborn reflexes, also called primitive reflexes or infant reflexes, are automatic involuntary movements that all healthy babies make in response to specific stimuli. These reflexes are controlled by the brainstem and are present from birth, serving vital functions for survival and development.

When we think about human movement, we usually imagine deliberate actions controlled by our conscious mind. However, newborn babies cannot yet control their movements voluntarily. Instead, they rely on a set of built-in, automatic responses called primitive reflexes. These reflexes have evolved over millions of years to help newborns survive during their most vulnerable period of life.

Primitive reflexes are fundamentally different from the reflexes we retain throughout life, such as blinking when something approaches our eye or the knee-jerk response when a doctor taps below your kneecap. While these adult reflexes remain with us forever, primitive reflexes are designed to be temporary. They serve their purpose during infancy and then gradually disappear as the baby's cerebral cortex (the thinking part of the brain) develops and takes over control of movement.

The presence of these reflexes at birth is one of the first things healthcare providers check during a newborn examination. Their presence indicates that the baby's nervous system has developed normally in the womb. Equally important is their disappearance at the expected times, which signals that the higher brain centers are maturing properly and beginning to control voluntary movement.

Understanding these reflexes can help parents appreciate the remarkable development happening in their baby's brain during the first year of life. Each reflex that disappears represents a major milestone in neurological development, paving the way for intentional movements like reaching, grasping, crawling, and eventually walking.

Why do babies have primitive reflexes?

Primitive reflexes serve three essential purposes in newborn life. First and foremost, they promote survival. The rooting and sucking reflexes, for example, are absolutely critical for feeding. Without these automatic responses, a newborn would be unable to find the breast or bottle and would not know how to extract milk. These reflexes ensure that even the most inexperienced newborn can feed successfully from the first day of life.

Second, primitive reflexes provide protection. The Moro reflex, sometimes called the startle reflex, is believed to be an evolutionary holdover from when human infants needed to cling to their mothers. When a baby experiences a sudden sensation of falling or a loud noise, the Moro reflex causes them to throw their arms outward and then bring them back in, potentially grabbing onto a caregiver. Similarly, the diving reflex protects babies from inhaling water if they accidentally go underwater.

Third, primitive reflexes serve as developmental markers that allow healthcare providers to assess neurological health. Each reflex appears and disappears according to a predictable timeline. When reflexes are absent at birth or persist beyond their expected disappearance age, it may indicate underlying neurological concerns that warrant further investigation.

What Are the Feeding Reflexes in Newborns?

The feeding reflexes include the rooting reflex (turning toward touch on the cheek), sucking reflex (rhythmic sucking when mouth is stimulated), and swallowing reflex (automatic coordination of swallowing). These reflexes work together to help newborns feed effectively from birth.

Feeding is the most important activity for a newborn, and nature has provided babies with a sophisticated set of reflexes that work together to make feeding possible. These reflexes are so well-developed that babies begin practicing them before birth, often visible on ultrasound as thumb-sucking in the womb.

Rooting reflex

The rooting reflex is the first step in the feeding process. When you gently stroke a baby's cheek or the corner of their mouth, they will automatically turn their head toward the touch and open their mouth. This reflex helps babies locate the breast or bottle without needing to see it. The rooting reflex is particularly strong when babies are hungry and may be less pronounced when they have recently fed.

Parents often notice the rooting reflex during the first few weeks when their baby seems to be searching for food by turning their head back and forth with mouth open. This is not random movement but a purposeful reflex designed to help them find nourishment. The rooting reflex typically disappears around 4-5 months of age, by which time babies have developed enough head control and visual coordination to find their food source voluntarily.

Sucking reflex

Once a baby has found the breast or bottle nipple, the sucking reflex takes over. When something touches the roof of a baby's mouth, they automatically begin making rhythmic sucking movements with their tongue and mouth. This reflex is remarkably sophisticated, involving the coordinated action of over 20 different muscles.

The sucking reflex is actually present before birth. Ultrasound examinations often capture babies sucking their thumbs or fingers in the womb, which is why some babies are born with small calluses on their hands. This prenatal practice ensures that babies are ready to feed immediately after birth. The sucking reflex begins to integrate into voluntary sucking around 3-4 months but remains strong throughout the first year as babies continue to need breast or bottle feeding.

Swallowing reflex

The swallowing reflex coordinates with sucking to ensure that milk goes down the esophagus to the stomach rather than into the airways. This reflex automatically closes off the airway when swallowing occurs, protecting the baby from choking. The coordination between sucking, swallowing, and breathing is one of the most complex automatic processes that newborns perform.

Unlike other primitive reflexes, the swallowing reflex remains with us throughout life, though it becomes more sophisticated as we develop. In newborns, this reflex ensures that the coordination between breathing and feeding is maintained, even though the baby has no conscious awareness of the process.

Babkin reflex

The Babkin reflex is a less well-known feeding-related reflex. When you gently press on both of a baby's palms simultaneously, they will open their mouth, bend their head forward, and sometimes turn their head to the side. This reflex can be used to stimulate sucking during breastfeeding by massaging the baby's palms.

The Babkin reflex demonstrates the interconnected nature of newborn reflexes. It shows that the feeding system is linked to hand movements, which may have evolutionary significance in helping babies hold onto their mothers while feeding. This reflex typically disappears around 3-4 months of age.

What Are the Grasp Reflexes?

Grasp reflexes include the palmar grasp (closing fingers around objects placed in the palm) and plantar grasp (curling toes when the sole is touched). The palmar grasp is so strong that newborns can briefly support their own weight, though this should not be tested unsupported.

The grasp reflexes are among the most fascinating primitive reflexes because they demonstrate the remarkable strength that newborn babies possess. These reflexes are believed to be evolutionary remnants from when primate infants needed to cling to their mothers' fur for survival.

Palmar grasp reflex

When you place your finger in a newborn's palm and press gently against the base of their fingers, they will automatically close their fingers tightly around your finger. This grip is remarkably strong. In fact, the palmar grasp reflex is so powerful that a newborn can momentarily support their entire body weight if they grip something while being lifted. However, parents should never test this unsupported because the reflex can release suddenly without warning.

The palmar grasp reflex is fully present at birth and remains strong for the first few months of life. As the baby's voluntary grasping develops, the automatic reflex gradually fades. Most babies lose the palmar grasp reflex around 4-6 months, which coincides with the development of voluntary reaching and grasping. This transition represents a major milestone in motor development.

Parents often enjoy the experience of having their newborn grip their finger, and this interaction is an important part of early bonding. The tight grip may seem like the baby is deliberately holding on, but it is entirely automatic at this stage.

Plantar grasp reflex

Similar to the palmar grasp, the plantar grasp reflex occurs in the feet. When you press your finger against the ball of a baby's foot, just below the toes, the toes will curl downward as if trying to grip your finger. This reflex is also very strong in newborns.

The plantar grasp reflex persists longer than the palmar grasp, typically disappearing around 9-12 months of age. Its disappearance is necessary for the development of normal walking. The reflex needs to integrate before babies can stand properly on flat feet and take their first steps.

Both grasp reflexes demonstrate how the newborn brain is wired for holding on tightly. In our evolutionary past, this would have been essential for infant survival when mothers needed to carry babies while moving through environments.

What Is the Moro Reflex?

The Moro reflex, also called the startle reflex, occurs when a baby experiences a sudden loss of support, loud noise, or other startling stimulus. The baby throws their arms and legs outward, spreads their fingers, extends their neck, then brings their limbs back toward their body. It typically disappears by 5-6 months.

The Moro reflex is one of the most dramatic and easily observed primitive reflexes. Named after Austrian pediatrician Ernst Moro who first described it in 1918, this reflex is sometimes called the startle reflex or embrace reflex because of the characteristic pattern of movement it produces.

When triggered, the Moro reflex causes a baby to throw their arms out to the sides with fingers spread wide, extend their legs, arch their back, and often cry. This is immediately followed by a secondary movement where the arms come back together across the chest in what looks like a self-embrace, and the legs flex. The entire sequence takes only a couple of seconds.

The Moro reflex can be triggered by several stimuli. The most common triggers include a sudden sensation of falling (such as when a baby's head drops backward unexpectedly), loud noises, sudden movements, bright lights, or any other abrupt change in the baby's environment. This is why babies often startle during diaper changes or when being put down.

Evolutionary significance

Scientists believe the Moro reflex evolved as a protective mechanism. In our ancestral past, when an infant felt themselves falling, the outward arm movement would have helped them grab onto their mother's body or fur. The subsequent inward embrace movement would have secured their grip. Even though human babies no longer need to cling to their mothers in this way, the reflex persists as a reminder of our evolutionary history.

What parents should know

The Moro reflex can sometimes disturb a baby's sleep. When a sleeping baby experiences a small startle, the reflex can wake them up and cause crying. This is one reason why many parents find that swaddling helps their newborns sleep better. Swaddling restricts arm movement, which can prevent the reflex from fully expressing and disturbing sleep.

The Moro reflex typically begins to diminish around 3-4 months and should be completely gone by 5-6 months. If the reflex persists beyond this age, or if it appears abnormally weak or asymmetrical from birth, it may warrant discussion with a healthcare provider.

What Is the Stepping Reflex?

The stepping reflex, also called the walking reflex, occurs when a baby is held upright with their feet touching a flat surface. The baby will make stepping movements as if trying to walk. This reflex disappears around 2-3 months but reappears when the child actually learns to walk.

The stepping reflex is one of the most surprising reflexes for new parents to observe. When you hold a newborn in an upright position with their feet touching a flat surface like a table or the floor, they will begin making alternating stepping movements with their legs, as if trying to walk. This reflex is present from birth, even though actual walking won't develop for another 9-15 months.

It's important to understand that this is not true walking. Newborns cannot support their own weight, and the reflex is simply an automatic response to having the soles of their feet touch a surface while in an upright position. The baby is not consciously trying to walk, and the movements lack the balance and weight-bearing necessary for actual locomotion.

The mysterious disappearance and reappearance

One of the most interesting aspects of the stepping reflex is its timeline. The reflex is strong at birth but disappears around 2-3 months of age. For many months, the baby shows no stepping behavior at all. Then, when the child is developmentally ready to walk (usually around 9-15 months), stepping behavior reappears, but this time as voluntary, purposeful movement.

Scientists initially thought the reflex disappeared because the neural pathways controlling it were "pruned" away during brain development. However, research has shown that the pattern generators for stepping remain intact throughout this period. The reflex appears to disappear simply because babies' legs become too heavy relative to their muscle strength to perform the stepping motion against gravity. When babies are placed in warm water that supports their body weight, they continue to show stepping movements even during the period when the reflex seems absent.

What Is the Babinski Reflex?

The Babinski reflex occurs when you stroke the outer edge of a baby's foot from heel to toe. The big toe extends upward and the other toes fan out. This response is normal in babies but would indicate neurological problems if present in older children or adults. It disappears around 12-24 months.

The Babinski reflex, named after French neurologist Joseph Babinski who described it in 1896, is a unique primitive reflex that healthcare providers commonly use to assess neurological function. When you stroke the outer edge of a baby's foot from the heel toward the toes, the baby's big toe will extend upward while the other toes fan outward. This is the opposite of what happens in older children and adults, who curl their toes downward in response to the same stimulus.

This reflex demonstrates an important principle about neurological development. In newborns, the spinal cord pathways that control foot movement are not yet under full control of the brain's motor cortex. As the nervous system matures and the corticospinal tract (the pathway connecting the brain to the spinal cord) fully develops, the response changes from extension to flexion.

Clinical significance

The Babinski reflex is one of the most clinically important primitive reflexes. In babies under 12-24 months, an upgoing toe response (positive Babinski) is completely normal. However, in children over 2 years old and in adults, a positive Babinski sign suggests damage to the corticospinal tract and requires immediate medical evaluation.

For this reason, the Babinski reflex is routinely tested during neurological examinations throughout life. In adults, it helps doctors detect conditions such as stroke, multiple sclerosis, spinal cord injury, or brain tumors that may have damaged the motor pathways.

What Is the Diving Reflex?

The diving reflex is an automatic response that protects babies if they go underwater. The baby automatically holds their breath, their heart rate slows, and blood is redirected to vital organs to conserve oxygen. This reflex helps prevent drowning but babies should never be deliberately submerged.

The diving reflex, also known as the bradycardic response or mammalian diving reflex, is a fascinating protective mechanism that all humans possess, but which is particularly pronounced in newborns. If a baby's face comes into contact with cold water, several automatic responses occur simultaneously to protect them.

First, the baby automatically holds their breath to prevent water from entering the lungs. Second, the heart rate slows significantly (bradycardia), which reduces oxygen consumption. Third, blood is redirected away from the extremities and toward the vital organs, including the heart and brain, to preserve the available oxygen for the most critical tissues.

This reflex exists in all mammals and is an evolutionary adaptation for species that spend time in water. In humans, the diving reflex is strongest in infancy and gradually diminishes with age, though it never completely disappears. Cold water triggers a stronger response than warm water.

When Do Newborn Reflexes Disappear?

Different reflexes disappear at different ages as the nervous system matures. The rooting reflex disappears around 4-5 months, Moro reflex by 5-6 months, palmar grasp by 4-6 months, stepping reflex by 2-3 months, and Babinski reflex by 12-24 months. Persistence beyond these ages may need evaluation.

The timing of reflex disappearance is carefully monitored by pediatricians because it provides valuable information about a child's neurological development. Each reflex has a specific "window" during which it should disappear, reflecting the maturation of different brain areas.

What if reflexes persist?

When primitive reflexes persist beyond their expected disappearance age, it's called retained primitive reflexes. This can occur for various reasons, including neurological conditions, developmental delays, or lack of movement opportunities during infancy. Retained reflexes can interfere with the development of voluntary movements and may be associated with learning difficulties, coordination problems, or behavioral issues.

If you're concerned that your child's reflexes haven't disappeared on schedule, discuss this with your pediatrician. They can perform a thorough neurological assessment and, if necessary, refer you to specialists who can evaluate and address any underlying concerns.

When Should You Seek Medical Advice?

Seek medical advice if reflexes are absent at birth, appear weak or asymmetrical, persist beyond their expected age of disappearance, or if you notice any unusual movements or responses. Most variations are normal, but a healthcare provider can assess whether further evaluation is needed.

While most babies' reflexes develop and disappear normally without any intervention, there are situations when you should discuss concerns with your healthcare provider. Understanding what to watch for can help you identify potential issues early when intervention may be most effective.

Signs that warrant medical evaluation

• Absent reflexes at birth: If standard reflexes cannot be elicited during newborn examinations
• Asymmetrical reflexes: If a reflex is much stronger on one side of the body than the other
• Exaggerated reflexes: Unusually strong or prolonged responses
• Persistent reflexes: Reflexes that don't disappear by their expected age
• Late reappearance: Reflexes that return after they had already disappeared

It's important to remember that there is some normal variation in when reflexes appear and disappear. The timelines given are averages, and healthy babies may fall slightly outside these ranges. A single weak reflex or one that disappears slightly early or late is usually not cause for concern. Healthcare providers look at the overall pattern of reflexes and development, not just individual findings.

Can You Test Your Baby's Reflexes at Home?

Yes, you can gently observe most newborn reflexes at home through normal interaction with your baby. Stroking the cheek triggers rooting, placing a finger in the palm triggers grasping, and holding baby upright with feet touching a surface shows stepping. Avoid deliberately startling your baby to trigger the Moro reflex.

Observing your baby's reflexes can be a fascinating and enjoyable part of getting to know your newborn. Most reflexes can be safely observed during normal caregiving activities without any special equipment or techniques. Here are some ways to observe common reflexes:

Safe ways to observe reflexes

• Rooting reflex: Gently stroke your baby's cheek with your finger and watch them turn toward the touch with their mouth open
• Sucking reflex: Allow your clean finger to touch the roof of your baby's mouth during feeding preparation
• Palmar grasp: Place your finger in your baby's palm and feel them grip tightly
• Plantar grasp: Touch the ball of your baby's foot and watch their toes curl
• Stepping reflex: Hold your baby upright (supporting their head and body) with feet touching a flat surface
• Babinski reflex: Gently stroke the outer edge of your baby's foot from heel to toe

Remember that observing reflexes should be a gentle, bonding experience. If you have concerns about the strength or presence of any reflex, discuss them with your healthcare provider rather than repeatedly testing at home. Healthcare providers are trained to assess reflexes accurately and can identify subtle abnormalities that parents might miss.