Reflexes in Newborn Babies and Infants
You may be surprised to learn that many of your newborn’s actions are actually reflexes—reactions that happen automatically. These reflexive responses can include everything from your baby stepping up and down as you hold her above a surface to her turning her face as you stroke her cheek.
It turns out that your baby is born with these automatic responses. Some reflexes, like the tongue thrust reflex, last for months, whereas others, like the Moro reflex, can disappear in a matter of weeks.
Read on to find out more about the most common infant reflexes and how long each reflex is likely to last.
What Are Baby Reflexes?
A reflex is an automatic response your baby has to stimuli. For example, if you put your finger in her mouth, she will suck on it. Or if she sees a bright light, she will shut her eyes.
A reflex means that your baby is reacting involuntarily and not choosing a certain behavior. It’s not just babies who have reflexes—adults have them, too. But this article focuses on some of the reflexes that babies have.
Your baby is born with the rooting reflex, which is what helps him find your nipple when breastfeeding for the first time.
To see this “looking-for-the-nipple” reflex in action, simply stroke his cheek or mouth with your finger, and he will automatically turn his head toward your hand.
At first, your baby may root from side to side when breastfeeding, turning his head toward your nipple and then away, but by 3 weeks old, he’ll know to turn in the right direction and position himself to suck at your nipple. He will also do this with the nipple of a bottle if you're bottle feeding him.
Your baby develops the sucking reflex even before she is born. If you had an ultrasound while you were pregnant, you may have seen your baby sucking on her thumb while still in the womb.
Once your baby is born, she’ll automatically start sucking when your nipple is placed in her mouth or when it touches the roof of her mouth. If you’re giving her formula or expressed breast milk from a bottle, this reflex happens in response to the nipple of the bottle, too.
Sucking is actually a very complex skill for a newborn, so despite it being a reflex, some babies don’t suck efficiently at first. Over time, they get the hang of it.
A reflex you may notice in your baby’s first months is the Moro reflex—a startle response.
If your baby’s head falls back abruptly or if he is startled, he will respond by throwing his arms and legs outward, extending his neck, and quickly bringing his arms together. He may also cry. This reflex typically disappears after about two months.
In your baby’s first month, you may notice that she smiles in her sleep. This is often referred to as a reflexive smile, because it’s a response to an internal stimulus. These are not yet those “real” smiles you’re eagerly awaiting, which will happen in response to something your baby finds interesting or amusing.
During the second month, though, your little one may start smiling back at you when she is up and awake. These are “true” smiles that you might see when you make a silly face or give your baby a little tickle.
Be patient while the reflexive smiles are still happening. It won’t be long before they’re replaced with the real thing—that adorable gummy grin—and you’ll love seeing how happy you make her when you smile at her.
Tonic Neck Reflex
The tonic neck reflex, also known as the fencing posture, is a pretty simple but funny reflex. If your baby turns her head to one side, she will automatically straighten the arm on the same side, bending the opposite arm, as if she were fencing. En garde!
This reflex doesn’t happen for every baby, and, if your baby happens to be crying, she may not exhibit this reflex. The tonic neck reflex usually disappears completely when she’s about 5 to 7 months old.
Stroke the inside of your baby’s hand or the bottom of his foot and you’ll see this reflex in action. He’ll grasp your finger with his hand (palmar grasp), or curl the toes of his foot (plantar grasp).
Your baby’s hand grip is quite strong. If you put a rattle in his hand, he will hold on tight! And there's nothing like the feeling of him curling his fingers around your finger in a vice-like grip.
Just be aware that this is a reflex and your baby can let go at any time. This means he may drop his rattle, or let go of your finger without notice.
The palmar grasp starts to disappear when your baby is about 5 to 6 months old. The plantar grasp usually disappears around the time your baby is 9 to 12 months old.
You may be surprised to see your baby stepping in her first two months whenever you hold her under her arms (while supporting her head, of course). While holding her in this position, as soon as the bottoms of her feet touch a flat surface, she’ll start stepping up and down. It may even look like she’s walking on air!
Remember that this is just a reflex and isn’t a sign that your little one is getting ready to start walking. You’ll have to wait a little while longer for those true first steps.
Tongue Thrust Reflex
Babies are born with the tongue thrust reflex. If you try to insert something into your baby’s mouth (like a spoon, for example), she will push against it with her tongue.
This reflex disappears when your little one is about 4 to 5 months old.
Your Baby’s Reflexes at a Glance
This table provides a handy summary of certain reflexes you might observe in your baby. Remember that every baby is different, so the timing of these reflexes may vary.
|Reflex||When it may appear||When it may disappear|
|Smiling reflex||Birth||2 months old|
|Moro reflex||Birth||2 months old|
|Stepping reflex||Birth||2 months old|
|Rooting reflex||Birth||4 months old|
|Tongue thrust reflex||Birth||4 to 5 months old|
|Tonic neck reflex||Birth||5 to 7 months old|
|Palmar grasp reflex||Birth||5 to 6 months old|
|Plantar grasp reflex||Birth||9 to 12 months old|
It will be exciting and interesting to see the way your baby’s different reflexes evolve into more deliberate actions over time. It's all part of the joy and wonder of seeing your baby grow and develop right in front of your eyes.
Want to know what else is in store? Discover more about your baby’s growth and development here.
How we wrote this article The information in this article is based on the expert advice found in trusted medical and government sources, such as the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists. You can find a full list of sources used for this article below. The content on this page should not replace professional medical advice. Always consult medical professionals for full diagnosis and treatment.
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