What Is Sucking Reflex In Newborns?

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When your baby arrives in this world, they’ll be born with certain instincts that’ll help them adapt to the world outside your womb. One of them is their natural reflexes. Reflexes are natural involuntary actions or movements. While some of the movements might be spontaneous, others might be a reaction to a certain action. Often, healthcare providers check the reflexes of a newborn to find out if the nervous system and the brain are functioning well.

Reflexes in newborns can be strong or weak depending on when and how the baby was born. Factors like premature birth or congenital birth defects can influence the reflex actions of a newborn (1).

When Does The Sucking Reflex Develop?

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Babies often develop sucking reflexes while still inside the womb. It usually starts developing around the 21st week. During this time, the fetus will gradually start to suck on his/her thumb (2). While most full-term babies might start developing these reflexes soon after birth, it isn’t the same for premature babies. Premature babies, who are under 36 weeks of gestation, are often born with some health complications. One of them being feeding difficulties because they are usually unable to suck. They are generally fed through a tube into the stomach until their feeding and sucking reflexes develop (3).

Important Reflexive Responses Of Newborn Infants

Right at the onset, newborn infants have a low level of development due to which their reflexes are limited only to swallowing and sucking. However, these very reflexes are important for their survival. Here are the most important ones:

Rooting Reflex

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This reflex requires an external stimulus. When a newborn’s upper and lower lip, cheeks, corners of the mouth, or chin are stroked or touched by an object, the newborn immediately reacts by turning in the direction of the object and opening the mouth. They might even try grasping the object by their mouths. This reflex is known as rooting reflex and helps newborns to locate the source of their food. This reflex usually starts at birth and remains for up to 4 months.

Sucking-Swallowing Reflex

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When a newborn’s mouth area is touched, he/she will immediately open the mouth, grasp the object, and start with the suckling movement. As the liquid enters the mouth, the tongue automatically moves it back for swallowing. This reflex action helps in feeding the infant with a bottle or breast. However, it is not sufficient for feeding with a cup or spoon. This reflex develops at birth and continues for up to 4 months.

Gag Reflex

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When an object such as a solid piece of food or a spoon gets way back into an infant’s mouth, the infant would instantaneously propel it to the front of the mouth. This is known as gag reflex. This reflex protects an infant from swallowing any inappropriate substance or food that can be a choking hazard. The gag reflex is one of the main reasons why the introduction of solid foods is delayed for infants below the age of 4-6 months. This reflex usually starts to decline after 4 months. However, it can last a little longer in some babies and, on rare occasions, even in adults.

Tongue Thrust Reflex

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Each time the lips are touched, the newborn would instinctively extend the tongue out of the mouth. This reflex, again, helps in feeding the infant from the bottle or the breast but is not suitable for spoon-feeding or cup-feeding. This reflex is also seen at birth and usually lasts for up to 4 months. At times, it might even extend to 6 months (4).

As infants develop and mature, so will their natural reflexes. They will start developing skills that might be necessary for them to progress from a liquids-only diet to a slightly more solid food diet. Eventually, they’ll develop skills that’ll help them eat food with spoons and then move on to more solid finger foods once they develop grasping reflexes. Careful observation by caregivers is necessary here to help understand the baby’s needs based on these developments.