A reflex is an involuntary reaction or movement to a stimulus. Grasping reflex in babies is an innate reflex that involves the involuntary actions of fingers (1). For instance, when you give them your finger or an object, they try to hold or grasp it. Most responses of newborns and infants are reflexive in nature. These reflexes are known as primitive reflexes, infantile reflexes, or newborn reflexes. Reflexes indicate the brain and nervous system functioning and aid in fine and gross motor development. In this post, we explain the grasping reflex, its significance, when it typically disappears, and when to be concerned about it.
What Is The Grasping Reflex?
The grasping reflex is an involuntary action in which a baby wraps their fingers around your finger or an object that strokes their palm. It is an innate, primitive response of newborn babies to a mechanical stimulus (2). The grasping reflex is also called the palmar reflex, palmar grasp reflex, or Darwinian reflex. You can examine the reflex by first placing your baby on their back (supine position) when they are awake and alert. The examiner needs to stroke the infant’s palm with the index finger. You will notice the following two stages of the reflex (3).
Closing of fingers: The baby’s fingers undergo flexion to enclose the examiner’s finger. Clinging to the object/finger: The pressure applied to the palm produces traction on the fingers’ tendons, resulting in a clinging action. It could be difficult for you to pull out your finger gently at this stage since the baby would have a firm grip.
Palmar Grasp Reflex vs. Plantar Grasp Reflex
Grasping reflex usually refers to the palmar reflex, which occurs on stimulation of the palm. However, a similar reflex can be elicited from the soles and toes. When the reflex occurs on the feet, it is called a plantar reflex, plantar grasp reflex, or Babinski reflex. Below are the notable differences between the palmar and the plantar grasp reflex (3) (4).
Significance Of The Grasping Reflex
The original purpose of the grasping reflex is unknown. The reflex is believed to be vestigial since it may have been significant for our arboreal, primitive ancestors. Nevertheless, the reflex may make it easier for a newborn to interact with the environment. Newborns cannot organize movements to grab an object voluntarily. Therefore, the palmar reflex creates a basic motor pattern for easier interaction with various objects. The grasping reflex is controlled by regions of the brain and the spinal cord. A healthy grasping reflex, along with other primitive reflexes, is often considered a positive indicator of good central nervous system (CNS) and the peripheral nervous system (nerves from the brain and the spinal cord) health (2).
Age Range Of The Grasping Reflex
The grasping or palmar reflex appears during the 16th week of gestation or second trimester. The reflex may be visible during ultrasound scans with the baby grasping the umbilical cord. The grasping reflex is usually visible up to six months of age, and it may disappear by five months in some infants (5). Premature babies usually have this reflex at the same time as full-term babies are expected to.
Why Does The Grasping Reflex Disappear?
The grasping reflex disappears due to reflex integration by the higher brain centers (6). Reflex integration occurs when mature brain centers inhibit the reflex and modify it to become a voluntary action. This indicates the maturation of a baby’s motor cortex (a part of the cerebral cortex that controls movement). A mature motor cortex leads to better motor skills and the ability to perform voluntary actions. Thus, as the baby grows older, they do not need primitive reflexes since their nervous system is mature enough to perform vital actions voluntarily.
What If A Baby Does Not Have A Grasping Reflex?
The absence of grasping reflex in newborns could indicate an underlying abnormality within the central nervous system or the peripheral nervous system. The following problems and issues could lead to an absent grasping reflex (2).
Injury to the brain Injury to the spinal cord Damage to the nerves (peripheral nervous system) Prolonged compression and subsequent damage to the nerves Accidental head injuries or severe concussions during the newborn phase
The baby may display a weak palmar grasp reflex if they have movement disorders, such as cerebral palsy. Your baby’s doctor will assess the presence of the reflex at birth or during subsequent checkups. If your baby suddenly stops having a grasping reflex, consult your doctor promptly.
What If The Grasping Reflex Persists?
The retention of primitive reflexes, such as the grasping reflex, beyond the normal age range indicates failure of reflex integration by the higher brain centers. Below are some of the neurological problems and conditions that could cause the persistence of grasping reflex beyond six months (7).
Spastic cerebral palsy Neuromuscular disorders, such as spastic hemiplegia Cortical lesions, such as due to brain injuries Diminished cortical activity due to injury or severe illness
Many of these conditions cause other symptoms, and they may be diagnosed as the baby grows older. Speak to a pediatrician if your baby continues to have a grasping reflex after six months of age.
Other Newborn Reflexes
Below are some of the other primitive reflexes present in newborns (8) (9) (10).
Asymmetrical tonic neck reflex (ATNR): It is also known as the fencing reflex. When the baby is placed on the back, their head will turn with the arm and leg of one side extended. In the meantime, the other arm and the leg will be flexed. This reflex disappears by the age of seven months.
Moro reflex: It is also known as the startle reflex. This reflex causes a baby to throw their head backward while extending their arms and legs when they hear a loud sound or experience a sudden movement. This reflex lasts for up to two to six months.
Rooting reflex: If the newborn’s cheek is stroked, the baby will automatically open the mouth and turn their head towards the side that was stroked. This reflex helps the baby find and latch to the breast or bottle nipple. The rooting reflex lasts up to four to six months.
Stepping reflex: Hold the baby upright with the soles touching the ground. The baby begins to shift the feet one after the other, resembling the stepping action. The stepping reflex disappears by the age of two to three months.
Sucking reflex: If the baby’s palate (mouth’s roof) and lips are touched with a finger, nipple, or pacifier, the baby starts making sucking motions. The sucking reflex usually disappears by four months.
Stroking the outer edge of the hand from the little finger to the wrist may stimulate the opening of a closed hand. Placing an object in the baby’s hand and bending their fingers around it. Then, gently tug at the object or twist it. Try placing colorful toys, rattles, and bells on the baby’s hand to encourage grasping.
