Shortly after your baby is conceived, she seems to be just a tiny little tadpole. But nine months later, she's a real person with five acute senses. How do those senses develop? Read on and find out.
Sense of Touch in the Womb
Just before the eighth week of gestation, an embryo develops its first sensitivity to touch. The first parts of its body to experience sensitivity are the ones that are the most sensitive in adults. It starts in the cheek and then quickly extends to the genital area (10 weeks), palms (11 weeks), and soles of the feet (12 weeks). By 17 weeks, the abdomen and buttocks are also sensitive. Your baby may experiment with this newfound sense of touch by stroking his or her face or sucking on a thumb, as well as feeling other body parts and seeing how they move.
By 32 weeks, nearly every part of the body is sensitive to heat, cold, pressure, and pain.
Sense of Taste in the Womb
By 13 to 15 weeks a fetus's taste buds already look like a mature adult's, and the amniotic fluid that surrounds the fetus can smell strongly of curry, cumin, garlic, onion, or other strong tastes from a mother's diet. Studies show that a fetus's swallowing increases when surrounded by sweet tastes and decreases with bitter and sour tastes.
During the last trimester, the fetus is swallowing up to a liter a day of amniotic fluid, which may serve as a "flavor bridge" to breast milk, which also carries food flavors from the mother's diet.
By birth, babies have a strong sense of taste. Newborns can discriminate between tastes and have shown definite taste preferences. Even preemies as young as 33 weeks suck harder on a sweetened nipple than on a plain rubber one.
Sense of Smell in the Womb
A fetus's nose develops between 11 and 15 weeks. Until recently, scientists didn't believe that fetuses would have any sense of smell, since it was assumed that smelling depended on air and breathing. However, the latest research has opened up a new world of possibilities.
The nasal system is made up of no less than four subsystems, and it's now believed that the amniotic fluid surrounding the fetus passes through the baby's oral and nasal cavities, triggering these senses.
Studies have shown that newborns are drawn to the odor of breast milk, although they have no previous experience with it. Researchers think this may come from cues they have learned in prenatal life.