Fetal Development
Your Baby’s World
When families are expecting a child, we try to visualize what he or she will look like when they finally emerge. Many of us have vivid dreams of our baby, or we pore over our ultrasound pictures, looking for minute details, like whose nose will baby inherit? And when baby is finally born, invariably, someone will count to make sure baby has all 10 fingers and 10 toes. In my own case, I remember learning that my baby needed to be delivered 2 months early, and going utterly blank with panic, wondering what exactly a 7-month fetus would look like, and what struggles we would face as a result.
In all of these examples, the focus is on the child’s size and physical appearance. Often the assumption is made that birth will be baby’s first experience with the outside world. But within the past 20 years, we have learned that nothing could be further from the truth. Your baby has been using his or her five senses to connect with you nearly from the start.
The first of baby’s senses to develop is his ability to touch. Skin, the body’s largest organ, is formed during the first trimester, and by week 8, your baby is already sensitive to the slightest stroke of a single hair on his cheek. Within the next 4 weeks many additional areas such as his palms, genitals and soles of feet become sensitive to touch, and your baby responds by beginning to explore his world, including sucking on his fingers, playing with his umbilical cord, and in the case of twins, even holding each other’s hands.
The next senses to emerge are taste and smell, which are closely connected and dependent upon each other. Research has proven that babies respond to changes in taste of amniotic fluid by 14 weeks, and that they also respond to differences in scent within the same time period, roughly 11-15 weeks, even before the structure of the nose is fully developed. Some research even suggests that mothers who eat a healthy and varied diet during pregnancy may later have toddlers who are more accepting of new foods! By the time they are born, newborn babies can identify their mother by her scent alone, and have already developed a preference for the sweet taste of their mother’s own milk.
At about 16 weeks gestation, babies begin to hear sounds, both those within their mother’s body, and those from outside. Far from the silent environment many people visualize, the womb is a noisy and stimulating environment. Babies hear their mother’s voice very clearly, and also can hear other voices quite well. They’ve even been shown to be able to remember and respond to familiar patterns of sounds. Two separate studies, one using Brahm’s Lullaby and one using The Cat and the Hat, showed that babies remember and respond to sounds they heard before they were born—all the more reason to go ahead and talk, sing, and read to your baby now!
Sight is the final sense to develop, and the only one which is not fully developed at birth. It is a myth that babies are born seeing in black and white. They can actually see quite well, but are nearsighted, seeing clearly at about 8-12 inches away—the exact distance between their own face and their parents’ while being held. While their eyes actually open at around 26 weeks gestation, they often respond to changes in light shining through the surface of their mother’s stomach even before this time.
During early pregnancy, your baby, while awake, is already responding to the outside world, to the sound of your voice and your breathing and heartbeat, and to your own activities. In addition, they have an active dream life. By 23 weeks, a sleeping fetus is also dreaming, 100% of the time. By birth this will decrease to 50% of the time. Most researchers believe their frequent dreaming to be connected to the intense level of brain development, which is occurring in these early months. Maybe someday science will find a way for us to know what they are thinking about, but for now, your baby’s dreams remain their own secret. Personally, I like to think they are dreaming of the day they will be born, and see their parents’ faces for the first time.
