A reflex is an action that is a response to a stimulus and that occurs without conscious thought. Examples of adult reflexes include pulling your hand away from a hot stove, and jerking your lower leg when your kneecap is tapped.
Babies are born with a unique set of reflexes that can tell a physician about their health and development. As soon as within the first minutes after birth, nurses and doctors assess these reflexes to determine a baby’s gestational age.
Some reflexes are present in infancy and last into adulthood. These include the gag reflex, which causes gagging when the throat is stimulated. However, other reflexes are unique to infants. Infants typically grow out of these reflexes within a few months of development. These reflexes include:
- grasp reflex
- Moro reflex
- rooting reflex
- startle reflex
- step reflex
- sucking reflex
- tonic neck reflex
- truncal incurvation/Galant reflex
Several of these reflexes are tested after birth. The criteria for measuring reflexes include the Apgar score and Dubowitz/Ballard Examination for Gestational Age. Apgar scores can determine whether a newborn seems to be healthy. The Dubowitz/Ballard Examination tests a baby’s gestational age. This test is typically performed within two hours of a baby’s birth.
Tests for neonatal reflexes aim to view how babies react to certain given stimuli.
The Moro reflex is tested by gently positioning a baby in a near-seated stance with the head supported. The tester lets the baby’s head drop backwards slightly, and then catches the head before it hits a pillow or mat behind it. If a baby’s Moro reflex is present, the baby should appear startled and lift its palms upward, with its thumbs out. When the baby is caught, the baby will bring its arms back to its body.
The Babinski reflex is tested by stroking the underside of the baby’s foot, from the top of the sole toward the heel. The baby’s toes will fan out and the big toe will move upward. In an adult, the foot and toes will curl inward.
The rooting reflex is commonly used to achieve a breastfeeding latch. When a baby’s cheek is stroked, the baby will turn toward the cheek that was stroked and will make a gentle sucking motion.
The grasp reflex is tested by placing a finger in the baby’s open palm. The baby will grasp the finger and can even maintain a firm grip on the finger.
A baby shows the tonic neck reflex when he or she is lying down and the head is turned gently to the side. This causes the baby to take on a “fencer” position. If the head is turned to the left, the right arm is extended and the left arm will reach straight away from the body with the hand slightly opened. If the baby’s head is turned to the right, he or she will assume the opposite position.
A healthcare provider tests the step reflex by holding the baby upright and gently touching its feet to a surface. The baby will appear to step or dance.
If an adult experiences a brain injury, he or she may exhibit infant reflexes once more. Examples of injuries that cause these symptoms include brain damage and stroke.
If you are concerned about your child’s development, you can ask a doctor to check these reflexes. Reflexes that return after they have previously subsided may be cause for concern.
This information is a summary. Always seek medical attention if you are concerned you may be experiencing a medical emergency.