Behaviorally speaking, there's little difference between a newborn
baby and a32-week-old fetus. A new wave of research suggests that the
fetus can feel, dream, even enjoy The Cat in the Hat. The abortion debate
may never be the same.
The scene never fails to give goose bumps: the baby, just seconds
old and still dewy from the womb, is lifted into the arms of its
exhausted but blissful parents. They gaze adoringly as their new child
stretches and squirms, scrunches its mouth and opens its eyes. To anyone
watching this tender vignette, the message is unmistakable. Birth is the
beginning of it all, ground zero, the moment from which the clock starts
ticking.
Not so, declares Janet DiPietro. Birth may be a grand occasion,
says the Johns Hopkins University psychologist, but "it is a trivial
event in development. Nothing neurologically interesting happens."
Armed with highly sensitive and sophisticated monitoring gear,
DiPietro and other researchers today are discovering that the real action
starts weeks earlier. At 32 weeks of gestation--two months before a baby
is considered fully prepared for the world, or "at term" --a fetus is
behaving almost exactly as a newborn. And it continues to do so for the
next 12 weeks.
As if overturning the common conception of infancy weren't enough,
scientists are creating a startling new picture of intelligent life in
the womb. Among the revelations:
o By nine weeks, a developing fetus can hiccup and react to loud
noises. By the end of the second trimester it can hear.
o Just as adults do, the fetus experiences the rapid eye movement
(REM) sleep of dreams.
o The fetus savors its mother's meals, first picking up the food
tastes of a culture in the womb.
o Among other mental feats, the fetus can distinguish between the
voice of Mom and that of a stranger, and respond to a familiar story read
to it.
o Even a premature baby is aware, feels, responds, and adapts to
its environment.
o Just because the fetus is responsive to certain stimuli doesn't
mean that it should be the target of efforts to enhance development.
Sensory stimulation of the fetus can in fact lead to bizarre patterns of
adaptation later on.
The roots of human behavior, researchers now know, begin to develop
early--just weeks after conception, in fact. Well before a woman
typically knows she is pregnant, her embryo's brain has already begun to
bulge. By five weeks, the organ that looks like a lumpy inchworm has
already embarked on the most spectacular feat of human development: the
creation of the deeply creased and convoluted cerebral cortex, the part
of the brain that will eventually allow the growing person to move,
think, speak, plan, and create in a human way.
At nine weeks, the embryo's ballooning brain allows it to bend its
body, hiccup, and react to loud sounds. At week ten, it moves its arms,
"breathes" amniotic fluid in and out, opens its jaw, and stretches.
Before the first trimester is over, it yawns, sucks, and swallows as well
as feels and smells. By the end of the second trimester, it can hear;
toward the end of pregnancy, it can see.
FETAL ALERTNESS
Scientists who follow the fetus's daily life find that it spends
most of its time not exercising these new abilities but sleeping. At 32
weeks, it drowses 90 to 95% of the day. Some of these hours are spent in
deep sleep, some in REM sleep, and some in an indeterminate state, a
product of the fetus's immature brain that is different from sleep in a
baby, child, or adult. During REM sleep, the fetus's eyes move back and
forth just as an adult's eyes do, and many researchers believe that it is
dreaming. DiPietro speculates that fetuses dream about what they
know--the sensations they feel in the womb.
Closer to birth, the fetus sleeps 85 or 90% of the time the same as
a newborn. Between its frequent naps, the fetus seems to have "something
like an awake alert period," according to developmental psychologist
William Filer, who with his Columbia University colleagues is monitoring
these sleep and wakefulness cycles in order to identify patterns of
normal and abnormal brain development, including potential predictors of
sudden infant death syndrome. Says Filer, "We are, in effect, asking the
fetus: 'Are you paying attention? Is your nervous system behaving in the
appropriate way?'"
FETAL MOVEMENT
Awake or asleep, the human fetus moves 50 times or more each hour,
flexing and extending its body, moving its head, face, and limbs and
exploring its warm wet compartment by touch. Heidelise Als, a
developmental psychologist at Harvard Medical School, is fascinated by
the amount of tactile stimulation a fetus gives itself. "It touches a
hand to the face, one hand to the other hand, clasps its feet, touches
its foot to its leg, its hand to its umbilical cord," she reports.
Als believes there is a mismatch between the environment given to
preemies in hospitals and the environment they would have had in the
womb. She has been working for years to change the care given to preemies
so that they can curl up, bring their knees together, and touch things
with their hands as they would have for weeks in the womb.
