Newborn baby reflexes

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Babies are born with a set of automatic, unconscious reflexes, 
a gift from our evolutionary past. Some of these are no 
longer useful—but they are all there for a reason. 

NEWBORN BABIES have so little control over their movements, it’s a wonder that they are able to survive at all. Yet humans have evolved so they are born with a large collection of instinctive reflexes—about 70 in total— which work automatically in the right situation. Many of these can be traced to our primate ancestors, when their function was crucial for survival. Reflexes help protect and guide a baby in those first months outside the womb, and they serve a variety of functions. Some, for example, ensure that a baby is ready to feed as soon as she is born, others are intended for self-protection. As the brain develops, these reflexes give way to more deliberate behaviors, and their disappearance is an important sign that the baby’s brain is developing properly.

ROOT REFLEX Within the first hour of birth, if a baby feels a touch on the side of her cheek she will turn her head and “root” in that direction. This ensures she can find mom’s breast or the nipple of a bottle. Yet scientists argue over whether rooting should in fact be considered a reflex, since it seems to be under a degree of conscious control. Rooting is less likely to happen if the baby is not hungry, or if she touches her own cheek, both of which suggest it is not as involuntary as other reflexes. 

SUCK REFLEX The rooting reflex prepares the baby to suck—when the roof of the mouth is touched the baby will begin sucking furiously. This reflex is not fully developed until the 36th week of pregnancy, which is why premature babies may have trouble feeding. The suck reflex primarily ensures that a newborn will instinctively eat, but sucking is also a key source of comfort for a baby. HAND TO 

MOUTH REFLEX While rooting and sucking are the most well-known feeding reflexes, another is the “hand to mouth” reflex. This is when a baby flexes her arm and brings her hand up to her mouth in response to a stroke on the palm of her hand or her cheek—she then sucks on her fingers. Initially, she lacks the strength to keep her hand in place for long, so the reflex remains until she is able to make this action consciously, and suck on her fingers when she feels the need. 

GRASP REFLEX If you put your finger in the palm of a newborn baby, she will grasp it tightly—a reaction known as the “palmar grasp” reflex. This reflex response is a throwback to our primate ancestors whose babies used it to cling to their mother’s fur as she moved around. The grasp reflex is also present in newborn babies’ feet, and this is another link to our evolutionary past, since baby monkeys cling with both their hands and feet. 

"Reflexes help protect 
and guide a baby in those 
first months outside the 
womb, and they serve a 
variety of functions."

STARTLE REFLEX If a baby feels as if she is falling, or she hears a loud noise, she will throw up her arms as if she is trying to grab onto something—a dramatic action called the “startle,” or “Moro” reflex. As with the grasp reflex, this stems from a baby’s primitive instinct to hold on and save herself. Babies can also experience a startle reflex when dropping off to sleep, so some parents swaddle their newborn to prevent her from waking herself up. STEP REFLEX When a newborn baby is held upright and feels a surface beneath her feet, she starts to move her legs as though she was walking. Although this “step” reflex seems to disappear at around two months, scientists have shown that if you place an older baby waist-deep in a tank of water (so that she feels weightless), the step reflex is still present. The reason they stop stepping is because accumulating baby fat makes it quite an effort to lift those little legs! The stepping reflex might also have other uses: before birth, babies use their legs to brace themselves against the wall of the womb and turn around; after birth, the step reflex helps the baby to push against mom during feeding and keep herself in the correct position. 

TONIC NECK REFLEX A baby lying on her back often turns her head to the side (usually to the right) and extends her arm in the same direction. This action—the “tonic neck” reflex—needs to disappear so that the baby can learn to roll over. In the meantime, it might protect newborns from rolling onto their tummies before they can lift their heads up properly. Scientists have speculated that babies’ preference for turning their head to the right is related to becoming right-handed later on.

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