Infant reflexes


Infant reflexes may confuse parents!

Parents sometimes mistake their baby's reflex actions as either...

  • A symptom of a problem; or
  • A deliberate action that indicates their baby is trying to communicate a need for something.

The purpose of this article is to highlight only the reflexes that frequently cause concern or confusion for parents. (Your child also has many other reflexes not mentioned in this article.)


What are reflexes?

A reflex is a movement or action that is performed involuntarily or automatically.  Reflexes perform many of our basic bodily functions. They occur without having to think about it. We have no control over many of our body's reflex movements.

Many of your newborn baby's body movements are due to reflexes. Some reflex movements occur spontaneously as part of your baby's normal day to day activity, others occur in response to certain triggers.

Reflex movements which are generally seen only in infancy are called 'Primitive or Infantile Reflexes'.  Many of your baby's primitive reflexes are related to feeding. These early reflex actions ensure your baby's survival until she has developed enough, both physically and cognitively (thinking), to intentionally control her body movements. Most primitive reflexes will disappear before your baby is 4 months old, but some can last for a long as a year.

Your baby also has many reflexes, which will remain throughout her entire lifetime, many of these you will recognize in yourself.


Primitive reflexes

Primitive reflexes include (among others)...

  • Startle reflex (Moro reflex)
  • Rooting reflex
  • Sucking reflex
  • Grasp reflex (Darwinian reflex)
  • Hand to mouth reflex
  • Tongue thrust (Extrusion reflex)

Startle (Moro) reflex

When your baby arches her back, throws back her head and flings out her arms and legs, then pulls her arms and legs in close to her chest and cries, she is demonstrating the startle reflex.  This reflex is an attempt to avoid a fall and to grasp on to something. Babies often startle with a loud noise; a sudden movement; a change in position; or a change in temperature, such as when you undress her. This reflex, which is often fading by around 8 weeks of age, is sometimes mistaken as a sign of fear or pain.

Rooting reflex

The rooting reflex, also called the 'search reflex', is nature's way of helping a baby to find the breast. This reflex is triggered when your newborn baby's cheek is touched or stroked along the side of her mouth. She will turn her head and open her mouth toward the touched side as she seeks something to suck.  The rooting reflex usually disappears by around 3 to 4 months of age but in some babies it may last as long as 12 months. The rooting reflex is often mistaken as a sign of hunger.

Sucking reflex

The sucking reflex, which is present in most full-term babies and some pre-term babies, usually fades by around 3 months of age. This reflex is triggered by inserting a finger, pacifier or nipple into your newborn's mouth. The sucking reflex is strongest when the palate is stimulated. The sucking reflex is an automatic response and not a clear sign of hunger. (Of course a baby will suck when she's hungry, but she will also suck when she's not.)

Sucking not only provides a source of nourishment, it also has a calming effect for babies. The urge to suck is stronger in some babies than in others. Many babies, particularly those under 3 months of age, will want to suck for periods of time in addition to when they are feeding.

Hand-to-mouth reflex

Babies also have a hand-to-mouth reflex that goes with the rooting and sucking reflexes. This reflex may be set off by either stroking your baby's cheek or the palm of her hand. The stroking causes your baby to root, her arm to flex and bring her hand to her mouth. Sucking on fingers or hand is often mistaken as a sign of hunger.

Sucking provides comfort for young babies. By around the age of 3 months, as this reflex fades, your baby has gained enough control over her arms to intentionally suck on her fingers and hand. Once she has discovered this skill, she may do it often. When parents first notice an increase in the amount of time their baby sucks their fingers or hand at this age it is often mistaken as a sign of teething.

Tongue thrust

While the tongue thrust or 'extrusion reflex' is present, if a baby's lips are touched her tongue automatically moves forward. Tongue thrust aids feeding from the breast or bottle but not solid foods. This reflex generally fades by around 3 or 4 months of age but for some babies it will remain active for longer. While this reflex is still active, if solid foods are offered it appears like your baby is pushing the food out of her mouth with her tongue. This reflex is often mistaken as dislike of food. Although this is not the case, a tongue thrust is a sign that your baby is not ready to eat solid foods.

Grasp reflex

Stroking or touching the palm of your newborn baby's hand will automatically trigger the grasp reflex, which makes her clench her fist. This reflex enables your baby to hold on and acts as a type of insurance against falling. The grasp reflex lasts only a couple of months and is stronger in pre-term babies. Because a baby will hold on tightly, this reflex is sometimes mistaken as fear of being alone.


Life long reflexes

Your baby was also born with many reflexes that will remain throughout her lifetime. Breathing, blinking, sneezing, coughing, yawning are to name only a few. Three reflex actions that commonly cause concern or confusion for parents of young babies are...

  • Gastro-colic reflex
  • Defecation reflex
  • Gag reflex

Gastro-colic reflex

When a baby sharply pulls away from the breast or bottle, fidgets, grunts, passes some gas or a poop and then returns to feeding, this is due to the gastro-colic reflex. This is normal infant behavior! Feeding stimulates the gastro-colic reflex, which triggers an urge to poop. Sometimes a baby will poop, sometimes pass gas, other times there will be nothing to show for his efforts. When observed during feeding this reflex is often mistaken as a sign of pain.

Hypersensitivity of the gastro-colic reflex, which presents as frequent spasms which occur in waves that continue on and off for hours, is one of the many theories on causes of infant colic in babies younger than 4 months.

Defecation reflex

Another related reflex is the defecation reflex, also known as the 'rectal reflex'. (Defecation is the name give to the act of having a bowel motion). This reflex is triggered by the expansion or filling of your baby's rectum (the part of his bowel closest to his anus).

Effective emptying of the rectum relies on both the defecation reflex AND increasing pressure in the abdomen by a 'straining' action, which assists to push the stools out. Babies commonly grunt, groan, go red in the face and appear to strain when this reflex is triggered. This behavior, which is an automatic response to the defecation reflex, is often mistaken as a sign of constipationAfter toilet training a child has learned to control and delay this reflex response.

Gag reflex

The gag reflex is a common source of concern for parents, particularly when their child first starts to eat solid foods. The gag reflex is often mistaken as choking. Unlike choking, which is silent, gagging is very noisy. The gag reflex protects your child from choking.

The gag reflex remains with us throughout life. Adults rarely gag because they have learned how to eat. While learning to eat solid foods, your baby needs to lean how much to move it around her mouth (so that it can mix with saliva) and/or how much to chew her food before attempting to swallow it. If she tries to swallow it too soon she may gag... BUT she also learns! Eating without gagging is a skill she will only learn with practice.

Written by Rowena Bennett
RN, RM, MHN, CHN, IBCLC, Grad Dip Health Promotion and author of 'Your Sleepless Baby: The Rescue Guide'.

Added March 2004. Revised 2008; Sept 2013.