Google is every new mom’s best friend. Newborns are so strange, so alien, and much of what they do — including those bizarre infant reflexes — easily elicits panic from nervous mamas. Any new parent’s search history will probably reveal some variation of these questions:
The good news: In most cases, everything is totally normal—even those weird infant reflexes. In this post, we’ll help put your mind at ease by explaining all of the most common newborn reflexes and how long they last.
What Are Infant Reflexes?
One of the more bizarre aspects of babies are all those infant reflexes. When your baby’s arm involuntarily stands up while he’s asleep, it’s enough to startle even the most stalwart mom. But rest assured, all those weird reflexes are a normal part of your baby’s developing nervous system and are there for very good reasons.
“Newborn reflexes are automatic responses to stimuli. The nature of a newborn reflex is that the baby doesn’t have to think about what to do, but rather does things instinctively.” — Edith J. Chernoff, MD, a pediatrician and an assistant professor of pediatrics at the University of Chicago.
We all have reflexes; or involuntary movements that are triggered by certain stimuli, but they can be quite pronounced in newborns and infants. All these jerks and kicks are vestiges of primitive survival instincts—the rooting and sucking reflexes, for instance, help baby learn to nurse successfully. Infant reflexes are necessary and important to proper nervous system development.
What Are Some Newborn Reflexes?
What it is: The rooting reflex, a reflex that’s present at birth, is triggered when the baby’s cheek or the corner of his mouth is touched or tickled. Baby will instinctively turn his head toward the sensation, open his mouth, and turn to the side, searching for the breast or bottle.
Purpose: The rooting reflex is a primitive method of survival. It is necessary for baby to find a food source in those first few weeks of life. A newborn will turn its head toward audio, olfactory, and visual cues, as well as touch (generally stroking the infant’s cheek), moving its head until a food source is found. (source)
How long it lasts: Once baby has had repeated success locating the food source, he/she will stop searching (moving the head around) and simply turn his/her head to latch. In breastfed babies this happens around 3 weeks old. Infants will still display signs of the rooting reflex until about 4 months of age, when movements become more voluntary rather than instinctual.
What it is: The reflex is triggered when the roof of the mouth is touched, usually by breast or bottle, but also by thumbs and fingers or a pacifier. But it’s not quite as simple as it sounds:
“Smooth functioning relies on adjusting the change in sucking pressure to the flow of milk … In other words, the newborn has to sense the coming flow of milk and adjust the sucking pressure of it ahead of time.” — Handbook of Developmental Psychology
Purpose: Another primitive survival reflex that does exactly what it sounds like it does—it helps baby learn to suck. This might be the most important reflex, since it helps baby suck and swallow milk, whether breast or bottle feeding. Interestingly, this reflex is one of the only behaviors that is more skilled in babies than it is in adults. (source)
How long it lasts: The suck reflex begins to emerge at around 32 weeks gestation and is fully developed around 36 weeks. (This is why some premature babies initially have a difficult time eating.) Baby will use the sucking reflex to eat until about 2-3 months of age, when she learn to perform the action of sucking on her own.
Moro Reflex/Startle Reflex
What it is: Though commonly known as the startle reflex, the moro reflex and the startle reflex actually have important distinctions. In both cases, baby startles as a result of external stimuli. The moro reflex occurs more slowly—baby will extend his/her arms or legs into the air, arch the back and the head, and curl his/her fingers, wrists, and elbows. The moro reflex is triggered when you go to lay baby down—it causes a sort of falling sensation. The startle reflex is similar, but occurs suddenly as a result of a loud noise or a sudden movement. When the startle reflex is triggered, baby generally doesn’t fully extend the way he/she does when the moro reflex is triggered.
Purpose: Both the moro and the startle reflexes are meant to protect baby from danger. Baby is learning to respond to something that seems dangerous and use his/her body to protect him/herself.
How long it lasts: Interestingly, the moro reflex will begin to fade between 3-6 months, but the startle reflex persists through adulthood. (source) The moro reflex is part of the reason some babies need to be swaddled—the sudden movement can wake them. You know the feeling: You’re sleeping and you dream you’re falling down the stairs. It’s scary and unpleasant to be startled awake like that, and that’s what baby’s feeling. According to studies, swaddling can “significantly inhibit spontaneous arousals” caused by the moro reflex.
Asymmetrical Tonic Neck Reflex (ATNR)
What it is: Also called the fencing reflex, tonic neck occurs when a relaxed baby is moved to the side. Baby’s head will turn to one side or the other, the arm on the opposite side will bend up at the elbow, and the arm on the same side as baby’s head will stretch out.
Purpose: This reflex develops early in the womb—at approximately 18 weeks. Experts say it promotes muscle development in-utero and makes it easier for baby to pass through the birth canal. Once baby is born, the reflex is important for the continuation of muscle development and helps build hand-eye coordination.
How long it lasts: This reflex can last up to 7 months.
What it is: The grasp reflex, or palmar grasp, is triggered when baby’s palm is stroked. When stimulated, baby’s fingers curl in toward the palm in a grasping motion.
Purpose: Experts say the purpose of the palmar grasp is probably to prepare baby’s muscles to voluntarily grasp objects, including food and toys, later.
How long it lasts: The grasp reflex lasts until baby is 9-12 months old, when baby begins to fine tune his/her motor skills. Fun fact: The palmar grasp may be able to help you predict whether baby will be right- or left-handed. One study suggests that the hand with the stronger grasp is likely the hand baby will show preference towards.
Babinski Reflex (Plantar Reflex)
What it is: The Babinski reflex, arguably the cutest of all newborn reflexes, is similar to the palmar grasp, but occurs in the foot. When the sole of baby’s foot is stroked, the toes flex up and out.
Purpose: This reflex is meant to protect the sole of the foot. When the toes flex up and out, it’s in an effort to distance skin from anything harmful that may be underfoot. Think about it like this: You’re walking barefoot and, at the last second you notice a piece of glass on the floor. You instantly and involuntarily lift your foot off the ground to avoid stepping on it. That’s exactly what the plantar reflex is for. (source)
How long it lasts: This reflex is present until about 2 years old, but may disappear as early as 12 months.
What it is: When baby is held aloft, letting his or her feet touch a firm surface, the stepping reflex is triggered, causing baby’s feet to move in a walking or stepping motion. This happens despite the fact that baby can’t yet support his or her own weight.
Purpose: Experts say this reflex ensures the leg muscles develop properly, so baby can learn to walk.
How long it lasts: The step reflex usually disappears around 2 months of age.
What it is: Developing around 3 months of age, the landau reflex occurs when baby is held in a prone position (face down with his/her head to one side). Baby will raise their head and flex the back, also slightly flexing their legs.
Purpose: Experts say the landau reflex helps baby stand up straight and develop correct posture. This is likely because baby works the muscles in his/her neck, back, and core when the landau reflex is triggered. As baby gets stronger, you may notice him/her displaying a similar movement during tummy time.
How long it lasts: This reflex should start to disappear around one year of age.
What it is: When an infant is held aloft, facing down, and lowered toward the floor, the parachute reflex is triggered and their arms and legs splay outward, as if to catch themselves.
Purpose: This reflex is meant to protect babies (and adults) from injury if they fall. Think about it this way: You’re walking down the sidewalk and trip on a crack. Your first instinct is to throw your hands out to catch yourself. This is essentially what baby is doing when the parachute reflex is triggered.
How long it lasts: This primitive reflex is unique, because it develops later in infancy (usually around 9 months) and does not disappear—even full-grown adults have the parachute reflex!
How Long Do Infant Reflexes Last?
Almost all of these newborn reflexes won’t last forever. In fact, they fade pretty quickly, as baby learns to survive in the world on his/her own.
“Most newborn reflexes begin to fade by the second month, and most should be gone by around the fourth month” — Kenneth Wible, MD, medical director of the Pediatric Care Center at Children’s Mercy Hospitals and Clinics in Kansas City, Mo.
A few reflexes, like the palmar grasp and the step reflex, linger until baby is closer to 2 years old. And some, like the startle and the parachute reflex, never disappear!
What If My Infant Doesn’t Have These Reflexes?
Generally infant reflexes are a sign of typical neurologic development and let us know that everything is working correctly. Your pediatrician will check on baby’s development, including whether he/she has the appropriate reflexes, at well visits. If you have any concerns about your newborn’s reflexes, talk to your doctor.
What If These Infant Reflexes Don’t Go Away?
All babies are unique and develop at different speeds. Because of this, infant reflexes can last a bit longer in some children. There are no hard-and-fast rules about when newborn reflexes disappear, and there here is usually no cause for concern. In rare cases, persistent infant reflexes can signal neurological disorders. You should talk to your pediatrician if you have any questions about your baby’s development.
How About You?
Did any of your baby’s reflexes frustrate, amuse, or startle you? I’d love to hear your stories!