Your hardwired baby

By Published On: February 12th, 2013

Gently press a newborn’s palm, and he’ll wrap his tiny […]

palmarreflexGently press a newborn’s palm, and he’ll wrap his tiny hand around your finger—so tightly, sometimes, it feels like he’ll never let go. That sweet gesture of his is actually an instinctive response known as the palmar grasp reflex, and some scientists believe it might be left over from a time when an infant’s survival depended on his ability to cling—literally—to his mother. Other research suggests that newborns come with the palmar grasp reflex built in as a way to foster mama-baby bonding. (And if you’ve ever held a baby’s hand, you know it works.)
Palmar grasp is just one of a large set of automatic behaviors, known as the primitive reflexes, that newborns are equipped with—in some cases, even before birth. Although they can appear random, these reflexes are really preprogrammed tools for survival and the earliest beginnings of the sensory and motor skills newborns are already starting to develop.
“Basically, all the reflexes are there at the beginning of life to prepare the baby for survival,” explains Geoffrey Kenyota, MD, a pediatrician at Long Beach Memorial Medical Center in California. “The main ones are for eating and protecting themselves or for being able to call out to their parents to come and protect them.” So important are the primitive reflexes that your baby’s doctor will likely test them shortly after birth and again at your first few checkups. Eventually, though, the reflexes will vanish as your little one’s nervous system matures and he can control his movements voluntarily.
In the meantime, read on to learn more about some of the most significant primitive reflexes and what clues they offer about your baby’s health and development.
Palmar grasp reflex
What it is:
When you press or stroke your baby’s palm, he’ll tightly grip your finger.
Why it matters:
Some say this reflex encourages a loving bond between babies and caregivers. It might also be for protection, helping newborns cling to their parents. (Don’t be fooled though. While your baby’s grip is strong, it’s also unpredictable—he could let go at any time.) On the other hand, absence of this reflex on one or both sides could indicate a nervous system concern, according to scientists at the Osaka Medical Center and Research Institute for Maternal and Child Health in Japan. Keep in mind, though, that your baby’s grasp might not be very strong in the first couple of days after birth.
How long it lasts:
This response usually disappears by the time your baby is 5 to 6 months old.
Rooting
What it is:
If your baby is hungry, and you touch his cheek or mouth, he’ll turn his head toward your hand (or whatever was touching him).
Why it matters:
One of the most important newborn reflexes, rooting helps your baby find your nipple when he needs to eat.
How long it lasts:
The rooting reflex can last as long as four months, but as your baby gets better at feeding—within three weeks or so—he’ll be able to find your breast or a bottle without much searching.
Sucking
What it is:
When your breast or a bottle—or even your finger—touches the roof of your newborn’s mouth, he’ll squeeze the object between his lips and begin to suck.
Why it matters:
Like rooting, sucking is essential for a baby to feed properly. Not all infants suck well at birth, though, so expect a doctor to check your baby’s sucking reflex before you leave the hospital. “Babies who aren’t sucking properly are not going to do well with eating and are going to need some extra help until that reflex is stronger,” Kenyota advises.
How long it lasts:
Present before birth (perhaps you caught your little one sucking his thumb in an ultrasound image), the sucking reflex as an automatic behavior goes away within a few months. At that point, your baby can control his sucking voluntarily.
Tonic neck reflex
What it is:
When your baby’s head is turned to the right, his right arm straightens and his left arm bends upward (and vice versa). It looks a little like he’s fencing, so this reflex is sometimes known as the fencing posture.
Why it matters:
Says Kenyota, the tonic neck reflex is a precursor to hand-eye coordination. “It’s to prepare them to start reaching. You’ll notice that, after a while, they’ll want to grab whatever they happen to be looking at—often, it’s your necklace.” Try not to worry if you don’t notice the tonic neck reflex—it can be very subtle, according to the American Academy of Pediatrics. And when your baby is fussy, he might not do it at all
How long it lasts:
By the time your baby is 5 to 7 months old, this reflex should vanish.
Moro reflex
What it is:
If your newborn’s head falls backward or if he is startled by a loud noise, he’ll extend his arms and legs and then draw them quickly back toward his body. He might also shudder or cry.
Why it matters:
Sometimes called the startle reflex, the Moro reflex might have been useful in helping a baby get his parents’ attention if he was in danger.
How long it lasts:
The Moro reflex is often to blame for waking your sleeping sweetie just as you’re laying him down in his crib. Fortunately, it only lasts about two months.
Fun Fact: Making strides
In another primitive reflex, the stepping reflex, your newborn will place one foot in front of the other—as though attempting to walk—when you place the soles of his feet on a flat surface. But, of course, he can’t support his own weight yet.
Guided by instinct
According to Suzanne Colson, PhD, a retired nurse and midwife in England, understanding the primitive reflexes and how they work might help new moms breastfeed more successfully. In a study, Colson and colleagues observed 40 nursing moms to examine how the primitive reflexes relate to breastfeeding. Some of the mothers sat upright with their babies in a traditional “cradle hold.” Others, meanwhile, reclined, allowing their infants to nurse while lying tummy-down on mom’s abdomen.
Colson found that nursing from a laid-back position was more likely to stimulate newborn reflexes that assist in breastfeeding. For example, when babies rooted from a traditional, cradle position, it often appeared as though they were turning away from the breast, leading moms to believe their infants were refusing the feed. The babies lying on top of their mothers rooted in a way that made it easier for them to find the breast and latch on.