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The five senses of the baby during pregnancy

Many mothers ask what their baby's five senses are like at birth and whether or not they are innate. The first certain element is that the five senses have a link with the central nervous system through the nerve endings. Light, sounds, flavors and smells reach us thanks to specially created 'windows' to capture sensations and allow communication between the external and internal world. Recent literature reports scientific articles demonstrating the multisensory nature of the fetus and its development in utero. This uterine learning will be responsible for the subsequent development and modeling at the central level that will introduce the newborn to the outside world, in a real learning path. In humans, the maturation of all sensory systems occurs almost completely in the uterus.

Let's now analyze the five senses one by one:

  • TOUCH: Already at the eighth week there are tactile receptors in the area around the mouth. These receptors will then extend to the entire body within a few months. From some tests it emerged that by the tenth week the tactile sensitivity of the genital area is already high, at the eleventh that of the palms of the hands, at the twelfth that of the soles of the feet. These areas, even in adults, maintain a higher number of sensory receptors than other parts of the body. The fetus makes the first tactile experiments through the slight contraction of the uterine walls and the presence of amniotic fluid. At the thirty-second week the whole body shows reactions to tactile stimuli.

  • TASTE: Around the tenth week the fetus begins to drink the amniotic fluid, constantly perceiving its taste; swallowing is present and helps, like a massage, to form the skull. The taste organs appear mature by the fourteenth week. At the sixteenth week, with the first swallows, the fetus will begin to activate the digestive system and the ability to reabsorb water in the intestine. It has been seen ultrasonographically that in relation to the presence or absence of sweet or bitter substances in the amniotic fluid, the quantity of swallowed amniotic fluid varies. This was found by introducing these into the liquid and, when the substances were sweet, the fetus performed sucking and swallowing movements, while, when they were bitter or acidic, it made grimaces and attempts to close the mouth. All these 'tasting' moments will prepare him to recognize breast milk, which tastes and smells similar to amniotic fluid.

  • SMELL: It was seen only a few years ago that the baby experiences the sense of smell from the various chemical compounds that can cross the placenta, reach the amniotic cavity and come into contact with its oral, nasal and pharyngeal cavities. Recent discoveries show that the olfactory system develops between eleven and fifteen weeks. The little one is immersed in an environment rich in olfactory stimuli coming from the food that the mother eats and from the environment in which she moves. Only a few hours before birth the nasal mucosa adapts to the air phase and at birth, the newborn, guided by the smell of the skin, reaches the nipple. The recognition of olfactory stimuli experienced in utero (similar smells between liquid and breast milk) explains the attraction of newborns to the smell of breast milk, although they have not had previous experience of it.

  • HEARING: The uterine environment is rich in muffled, deep and rhythmic sounds, coming from the mother's body. The fetus receives many auditory stimuli: the mother's heartbeat, her voice, the passage of food in the digestive tract, the noises of the environment; she hears 'external' voices and reacts differently to different tones: when these are strong, the rhythm of her breathing changes, her limbs shake, her heartbeat accelerates. If the fetus hears quiet music, it enters a state of relaxation, its movements calm down, the heart rate decreases. Each experience will be memorized and will be part of his experience. In the development of the auditory system, the cochlea is already formed at eight weeks, the receptors begin to differentiate at ten weeks, and by the sixth month the entire auditory structure is created. At twenty-seven weeks the ability to discriminate between different sounds is present, the basics of language are learned thanks to prenatal sound exposure. From this moment the fetus is able to react to a considerable range of frequencies and to orient the head towards the source of the sound. Vestibular adaptation is very delicate and is related to the appearance of gravity and the numerous stimuli caused by the lower surrounding pressure. The ears, in addition to being the organs of hearing, contain the structures that provide balance and orientation in space. It seems that the fetus gets used not only to the intensity of the noise but also to its specificity. The maternal voice, for example, also having an internal resonance, is perceived and recognized better than the others even after birth.

  • SIGHT: At birth, sight is developed to such an extent that objects placed in front of the baby's face can be focused at a distance of 20cm. The movements of the eyes will be coordinated and this will allow the newborn to see things in three dimensions and not flat. The eyes are formed already seven weeks after conception and after ten there are the optic nerves that connect them to the central pathways. At the end of the eighth week the eye has an oval shape, the eyelids have just formed and the first pigments of the iris appear. At the seventh month the fetus keeps the eyelids open and shortly before it seems to be able to localize the visual stimuli showing to react, with accelerations of the heart rate, to beams of light projected on the maternal abdomen. At the end of the second month of pregnancy, the eyes are perfectly visible and begin to move incompletely. Visual acuity is not good until four to six months of life.

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