Infants are born with a number of vital reflexes that help them to survive. One of these is the swallowing reflex, which plays an important role in breastfeeding. Because sucking and swallowing are the main components of breastfeeding, this reflex is often called the "sucking reflex" or the "suck-swallow" reflex.
The suck-swallow reflex is one of the first reflexes demonstrated by the developing infant. This behavior can be observed during gestation. It typically begins to appear around the 12th to 13th week of pregnancy. During this period, the fetus may demonstrate the beginnings of this reflex by sucking its thumb, yawning or making swallowing motions. By 36 weeks, the reflex is usually fully developed. When born, the infant should be able to suck and swallow immediately.
The suck-swallow reflex is a vital part of the feeding process of infants. Pressure of an object against the roof of the mouth triggers the sucking reflex. Infants will often suck any object, such as a finger, which touches this region. When feeding, the sucking reflex draws milk from the breast or bottle. As milk enters the mouth, the swallowing reflex initiates. The two reflexes work together, allowing the infant to swallow milk while simultaneously sucking to draw out more.
Unlike the other reflexes associated with feeding, swallowing remains reflexive as the infant develops into an adult. Adults can consciously suppress swallowing, but it is usually triggered by a reflex as the tongue moves food into the back of the mouth. The rooting reflex, which turns the infant's head toward any object which touches its mouth or cheek, disappears at around four months as the child learns to direct its own head movements, while the suck reflex lasts until the infant is around one year old.
The swallowing reflex is crucial to infant nutrition. When the reflex fails to function properly, the child's health can be endangered. A number of different conditions affect this reflex. Premature infants or infants suffering from other conditions such as cerebral palsy may not have fully developed swallowing reflexes. The swallowing reflex may not be present, or the coordination between sucking, swallowing and breathing may be impaired. This can lead to choking as milk blocks the child's airway.