Reflexes in Newborns

Reflexes Babies Are Born with

Babies come into the world helpless and completely dependent on others to protect them and care for them. That much, we all know. But it turns out that newborns come equipped with a number of instincts — reflexes that will help insure a baby’s survival from the start, even before the infant has had a chance to learn how to do anything. Doctors test reflexes as a way to assess how well infants’ nervous systems are developing.

Most newborn reflexes start fading by the second month, and they’ve generally disappeared by the fourth month. Doctors caution that if baby reflexes continue beyond the fourth to sixth month, parents should tell that to their pediatrician, as it could possibly indicate that there is a neurologic concern.

Let’s look at some reflexes or instincts that newborns are born with, which gradually disappear as the baby becomes more “mature.”

Rooting Reflex:

The rooting reflex makes a baby turn her head (toward the nipple) when her cheek or mouth is stroked. This reflex helps the infant find the nipple when she is hungry. At first, the newborn may turn her head from side to side, then eventually place her mouth on the nipple; by about three weeks, the infant simply moves her head to the side and opens her mouth.

The rooting reflex is gone by four months of age, at which point the baby is able to make the deliberate decision to search out the nipple when she is hungry.

Sucking Reflex:

This reflex causes a newborn and young baby to forcibly suck on an object that is put in their mouth. We know from ultrasounds that have been taken in recent years that the sucking reflex is present in an infant even before birth, as we have seen images of babies inside the uterus sucking on their thumbs.

After birth, when an object is placed in a baby’s mouth, the infant begins to suck. That of course serves the purpose of ensuring that a baby will be able to eat right from the start. Sucking behavior does not disappear; but by four months, it becomes voluntary, rather than instinctual.

Palmar Grasp or Grasping Reflex:

Put any object — a finger, a hair strand, a necklace — against the palm of a newborn, and you will see that the baby immediately makes a fist and grabs tightly whatever is placed in their palm. The palmar grasp or grasping reflex is very strong even in premature infants; doctors say it appears as early as 16 weeks into a pregnancy. It is present in babies until 5 to 6 months after birth.

Moro Reflex or Startle Response:

When a newborn is startled by an outside stimulus — such as a loud noise, a sudden movement of his body, a bright light or even a strong smell — the baby will throw his arms and legs out, fingers spread out, then quickly bring arms and legs back toward his trunk. The moro reflex disappears at around 3 to 6 months.

Stepping Reflex:

If you hold a newborn upright, supporting her head and placing the soles of her feet on a firm surface, she will begin “taking steps” — alternately placing each foot down as though walking. The purpose of this reflex is obviously to prepare the infant for walking. It disappears by the second month, but it comes back at around 12 months.

Doll’s Eyes Reflex:

Just like with a doll, if you hold your newborn in a horizontal position and she has her eyes closed but is awake, then you slowly raise her body to a vertical (standing up) position while still holding her, she will open her eyes, just like a doll. Lower the baby’s head back down, and the eyes close; bring baby’s head back up, and her eyes open again. This reflex disappears at about 3 to 4 months of age.

Prone Crawl Reflex:

The prone crawl reflex can be stimulated by placing your newborn face down on a flat surface. The baby will try to crawl forward using his arms and legs. This reflex will disappear by 3 to 4 months of age — only to reappear in the form of a deliberate behavior once he’s really ready to crawl a couple of months later!

Last, there is another newborn built-in behavior that results from your infant’s still-developing nervous system, which sends more electrical signals to muscles than necessary:

When your newborn is upset or crying, you may see that his chin, arms or legs will start trembling. As his nervous system’s signals become better coordinated, this shaking will diminish. Such quivering is normal at the start; but if the shaking continues to occur, is rhythmic or doesn’t stop even when you soothe and hold your baby, talk to your doctor about it.

The survival value is obvious in some newborn reflexes, but it is less apparent in others. However, in the case of all reflexes, doctors can test them and use them to determine whether or not a newborn’s neurological function is normal. If a reflex is absent or abnormal in a baby, it may indicate that there are problems with the infant’s central nervous system and further assessments may be done.

By Jamell Andrews