8. Can a Baby Hear Inside the Womb?
A baby can hear inside the womb.
But “hearing” in a fetus is really a matter of feeling vibrations in
the skull that are then transmitted to baby’s inner ear. It may be
similar to living near a busy airport.
The developing baby hears a constant
murmur of noises. By the middle of the second trimester, your baby will
begin hearing many sounds from you—your beating heart, lungs filling
with air, swishing blood and digesting food. Baby hears your voice as
it vibrates through your bones. Lower-pitched sounds are heard more
clearly in utero than high-pitched ones.
There is evidence
that by the third trimester the fetus responds to sounds it hears.
Researchers have noted fetal heart rate increases in response to tones
heard through the mother’s abdomen.
Too much noise may be harmful to an
unborn baby. A baby exposed in utero to noise levels between 85 and 95
decibels (common at rock concerts and dance clubs) is three times more
likely to suffer from high-frequency hearing loss.
Newborns prefer their mother’s
voice to a stranger’s, which suggests they recognize her voice. Babies
also prefer their mother’s native language, and they respond strongly
to a recording of an intrauterine heartbeat.
9. Problems for a Developing Fetus
During the embryonic period (the first
8 weeks of baby’s growth), the embryo is most susceptible to factors
that can interfere with its development. Most birth defects originate
during this period.
Some things that have a bad effect
(teratogenic) at one point in pregnancy are safe at other times;
rubella is one example. The most critical period is the first 13 weeks.
If the fetus is infected with rubella during the first trimester, heart
defects often occur. Infection later can be less serious for the fetus.
Time-Saving, Energy-Saving Tip
Do you sometimes find you just
don’t have time to wash your hair, but you want it to feel fresher? If
you have light-colored hair, an easy way to remove some oil and dirt is
to put a little baby powder in your palms (start with a little; add
more if you need it), and run hands through your hair. Start at the
front, and fluff your hair as you go. Brush briskly to distribute
powder through your hair and to remove oil and dirt. Style as usual.
10. Your Medication Use
Some medications you take could harm a
developing fetus; others are safe at any time during pregnancy. Still
others are safe for one part of pregnancy but not advised for another.
It’s best to avoid medications during pregnancy unless you discuss them
with your healthcare provider before taking them.
11. Premature Birth
It’s hard to believe, but today a baby
born at only 25 weeks gestation may survive. Some of the greatest
advances in medicine have been in the care of premature babies. Because
of advances in technology, fewer than 10 deaths per 1000 are reported
in premature births.
Critical Periods of Fetal Development
| Time Period |
Fetal Development Affected |
| 3 to 5½ weeks |
Central nervous system |
| 3½ to 5½ weeks |
Heart |
| 3½ to 7 weeks |
Upper and lower limbs |
| 3½ to 7½ weeks |
Eyes |
| 3½ to 8½ weeks |
Ears |
| 5½ to 8 weeks |
Teeth |
| 5½ to 8½ weeks |
Palate |
| 6½ to 9 weeks |
External genitalia |
| 20 to 36 weeks |
Brain and lungs |
However, babies born extremely
early are usually in the hospital a long time and often have serious
problems.
