Primitive Reflexes
The Importance of Primitive Reflexes for Infant Feeding
Sheridan Phillips, OTD, OTR/L, BCP, IBCLC
As new parents or caregivers, you may often hear terms like "primitive reflexes" and wonder what role they play in your baby's development—especially when it comes to feeding. Infant reflexes are automatic, instinctual movements that are present at birth and play a key role in survival and growth. These reflexes help babies adapt to the world around them, including the crucial task of feeding. Here we will explore the most common primitive reflexes related to feeding and how they support your baby's feeding skills.
What Are Primitive Reflexes?
Primitive reflexes are automatic movements that are hardwired into the brain and nervous system. They are essential for a baby’s early development and help them respond to stimuli before they have the ability to control their body voluntarily. These reflexes begin to fade as the baby matures and gains more control over their movements, typically disappearing within the first year of life.
Oral Primitive Reflexes
1. Rooting Reflex
The rooting reflex is an involuntary action where the baby turns their head and opens their mouth to “root” when their cheek or mouth is gently stroked. This reflex helps the baby find the breast or bottle, making it crucial for successful breastfeeding or bottle-feeding. The rooting reflex appears around 28 weeks gestation generally lasts until about 4 to 6 months of age. This reflex serves as the baby’s initial mechanism for finding nourishment. At birth, a newborn lacks the strength and coordination to seek out food on their own so this reflex helps guide them to the breast or bottle where they instinctively latch and begin suckling.
2. Sucking Reflex
The sucking reflex is another critical primitive reflex that kicks in when the baby’s lips are stimulated. When an object touches the baby’s lips or palate, they automatically begin to suck. This reflex is also vital for the baby’s ability to feed from the breast or bottle. It helps the infant create a seal around the nipple, which allows for efficient milk intake. The sucking reflex starts to appear around 32 weeks gestation and is fully formed by 36 weeks. It will start to integrate or disappear between 8-12 weeks and sucking will turn into a voluntary movement instead. This reflex also includes swallowing. If a baby has trouble sucking, it may affect their ability to feed effectively, which can lead to feeding problems and poor weight gain.
3. Gaping Reflex
This reflex occurs when a baby opens their mouth wide in response to tactile stimulation on their lips or chin. The gaping reflex helps the baby prepare for feeding by encouraging them to open their mouth wide enough to latch deeply onto the breast or bottle. The gaping reflex will appear around 32 weeks gestation and integrate around 4-6 months. A wide mouth is key for a proper latch, which allows for effective milk transfer. This reduces the risk of nipple pain or shallow bottle latch and is critical for baby to transfer milk.
4. Tongue Extension and Lateralization Reflex
In addition to the rooting, sucking, and gaping reflexes, tongue extension and lateralization are two other important primitive reflexes that help facilitate feeding in newborns. These will develop around 32 weeks gestation and will integrate between 7-9 months of life.
The tongue extension reflex occurs when the baby’s lips or the roof of their mouth are stimulated, prompting the baby to stick their tongue out. This reflex is particularly active when the baby is breastfeeding, as it helps to form a seal around the nipple and effectively draw milk.
The tongue lateralization reflex refers to the baby's ability to move their tongue from side to side. This reflex is often observed when something touches the side of the baby's cheek, gums, or lips, and the baby instinctively moves their tongue toward the stimulus. These reflexes are essential for the coordination of sucking, swallowing, and managing the milk flow. They also contribute to a baby’s ability to transition from breastfeeding to solid foods later on and are key for the development of more advanced feeding skills.
5. Phasic Bite Reflex
Another important primitive reflex related to feeding is the phasic bite reflex, which plays a crucial role as infants begin to develop the foundational skills for chewing and managing different textures of food. Although this reflex is primarily associated with the introduction of solids, it begins to emerge early in life and helps prepare the baby’s mouth for the complex processes of biting and chewing. It is a jaw movement that occurs when pressure is applied to the baby's gums or teeth. When something, such as a finger or a solid object, is placed against the baby’s gums, they will instinctively bite down, often in a repetitive or rhythmic pattern. This reflex usually begins to emerge in newborns and gradually becomes more coordinated over the first few months of life and should be fully developed around 3-4 months old. It typically integrates between 9-12 months old. The phasic bite reflex helps the baby begin to strengthen the muscles in their jaw and mouth. This is the first step in preparing the baby for more complex movements like chewing and grinding, which will be necessary when they begin eating solids and is part of how babies start to explore different food textures safely.
6. Gag Reflex
The gag reflex plays an important role in feeding, particularly during the early states of solid introduction. The gag reflex is a protective mechanism that helps prevent choking by triggering a reaction that pushes food or objects away from the back of the throat if they are too large or if the baby is at risk of swallowing them. This helps ensure the infant doesn’t inhale food or liquids into the airway. It is essential for developing oral motor skills. It helps babies learn how to manage textures and consistencies in their mouth. Over time, it gradually becomes less sensitive which allows the child to handle more complex textures and larger pieces of food. It typically develops around 24 weeks gestation. This reflex remains present throughout the lifespan but becomes less sensitive throughout the first year. If the gag reflex is oversensitive, it is likely that the baby’s tongue is not elevating fully to articulate with the hard and soft palate so they are not used to input in those areas, causing the gag reflex to kick in when a nipple or finger does touch it. The gag reflex can be desensitized with purposeful mouth play, gently rubbing the finger in a zig zag pattern from the front to the back of the palate, and exercises to help the tongue elevate and suction to the roof of the mouth independently.
Motor Primitive Reflexes
7. Palmar Grasp Reflex
The palmar grasp reflex occurs when something is placed in a baby’s hand, and they instinctively grip it. While this reflex is more commonly associated with physical development, it can play a role during feeding, especially when holding a bottle. As babies grow, they may start to hold onto a bottle or a breast during feeding. The palmar grasp reflex may help babies begin to engage in these activities as they move toward more independent feeding behaviors. It will also allow them to grasp lightweight objects and bring them to their mouth for oral exploration which can also promote good oral motor development.
8. Moro Reflex (Startle Reflex)
While the Moro reflex is not directly related to feeding, it can impact a baby’s feeding experience. This reflex occurs when the baby feels like they’re falling or hears a loud noise; they may throw their arms and legs out and then draw them back in. If a baby is startled during a feeding session, it may cause them to break their latch or stop feeding. Managing the Moro reflex by providing a environment during feeding can help reduce disruptions and allow for more successful feeding sessions. It develops around 28 weeks gestation and integrates between 4-6 months. Frequent swaddling may delay the integration of the Moro reflex so transitioning out of swaddles as early as possible to encourage more natural movement can help.
9. Asymmetrical Tonic Neck Reflex (ATNR)
This reflex, often referred to as the fencing reflex, occurs when a baby turns their head to one side, and the arm on that side extends while the other arm bends. While this reflex is not directly related to sucking or swallowing, it can influence the baby’s position during feeding, especially if they are nursing from one side. A baby’s ability to turn their head and find a comfortable position is essential for feeding. This reflex develops around 20 weeks and will integrate around 4-6 months allowing for more purposeful head and body movements during feeding.
10. Spinal Galant Reflex
This reflex involves the response of a baby to a light touch or stroking along the side of their spine, usually from the lower back toward the ribcage. The baby will usually flex their body toward the side that is being stimulated, resulting in an arching or twisting movement. It helps babies develop their trunk and core muscles. If the reflex is too strong or does not become fully integrated, it can cause the baby to have difficulty maintaining a stable, relaxed position during feeding and can affect the latch. This reflex is developed in utero around 20 weeks and should integrate between 3-9 months.
11. Tonic Labyrinthine Reflex (TLR)
This reflex is related to the vestibular system and is activated by the position of the head and the body in space. There are two distinct responses based on the baby’s position and direction of head movement. When the infant’s head tilts backward, often when laying on the back, the body will extend with the arms and legs straightening. When the infant’s head tilts forward, like chin moving toward chest, often while on the belly, the body will flex with arms and legs curling inward. This reflex plays a key role in early motor and sensory development. It helps the infant develop a balance between flexor and extensor muscles as well as head and postural control. It also helps develop the balance and spatial orientation of the vestibular system. This reflex develops starting at 12 weeks in utero and usually integrates around 3-4 months.
What Happens When These Reflexes Are Overactive or Retained?
Overactive or retained motor reflexes can cause issues with feeding, motor and sensory development, postural control, symmetrical movement, tummy time, and lead to increased body tension or stiffness. The overarching recommendation for integrating all overactive/retained reflexes is to encourage natural movement as much as possible. This involves less container usage, less swaddling, more baby wearing and encouraging motor milestones as appropriate for the baby’s age. Tummy time, side lying play, and facilitating rolling, sitting, and crawling are all important for the integration of reflexes. Bodywork or manual therapies such as craniosacral, fascial release techniques, and chiropractic care can decrease tension and encourage natural, symmetrical movement as well. Appropriate development and then timely integration of all primitive reflexes is essential for brain and neurological development, motor skills, and even behavioral regulation and academic skills later on.
What Happens When These Reflexes Are Delayed, Diminished, or Absent?
In some cases, a delay, diminished response, or absence of these reflexes may indicate a developmental issue. For example, if the rooting or sucking reflex is weak, the baby may struggle with breastfeeding or bottle feeding, leading to poor nutrition or weight gain. If you notice that your baby isn’t responding to attempts to elicit or you are not observing these primitive reflexes as expected, it’s important to consult with a health care professional trained in feeding and reflex development such as a pediatrician, physical or occupational therapist, or lactation consultant.
