Unborn Child Develops So Rapidly!
the following few paragraphs I've highlighted some of
the ways the child's body develops, with an emphasis
on the early stages of pregnancy - often on a day-by-day
basis. The developments I've chosen are only a few of
the hundreds of other things that are happening early
in pregnancy. I selected them because they captured
my imagination. Readers who browse through the appendices
will find information about other developments they
may find interesting.
before we begin, a comment might be in order about the
moment when it all gets started. A new human being is
conceived when a sperm fertilizes an egg. The sperm
has 23 chromosomes and so does the egg. But the fertilized
egg has 46, half from each parent, and is genetically
unique. These 46 chromosomes, which are fixed at conception,
establish the child's sex and are a blueprint for how
it will develop, both during pregnancy and after birth.
the child begins developing immediately after conception,
the most visible advances occur during the third to
eighth weeks. In fact, key organs are already developing
in the third week - a time when many women are just
beginning to wonder if they are pregnant.
vessels start to form very early, about 13-18 days after
fertilization. Then, on about the 20th day - nearly
the end of the third week - the foundation of the brain,
the spinal cord, and the entire nervous system is established.
eyes begin to develop early in the fourth week after
conception. During this extremely critical week the
esophagus, gallbladder, liver, lungs, pancreas, pharynx,
stomach, and trachea also begin to form. And, toward
the end of the week, the nose, tongue, and spleen also
start to develop.
heart begins to beat on about the 22nd day after conception,
circulating blood throughout the child. The arms begin
to form on about day 26, followed by the beginnings
of the legs on day 28, the same day that the mouth opens
for the first time. Also on the 28th day, building blocks
are present for 40 pairs of muscles that will run from
the base of the skull to the bottom of the spinal column.
kidneys begin to develop early in the fifth week after
conception. The jaws and ears are also forming during
this week and the face starts to look human.
intestines are defined at the end of the first month,
and the larynx is developing on about the 32nd day,
the same time that spinal nerves begin to sprout and
the palate is forming.
cerebral cortex, the part of the brain that controls
the intellect and motor activity, begins to differentiate
on the 33rd day after conception, the same day that
the forearms and shoulders can be distinguished. The
elbows are developing on the 34th day, as are both hand
and foot plates.
olfactory nerve, which is related to the sense of smell,
is present in the brain on the 35th day after conception,
the day when the ribs begin to form and lengthen.
the upper and lower lips are forming early in the sixth
week after conception. Also during the sixth week the
eye is obvious, reflecting the fact that retinal pigment
is already present. The beginnings of the eyelids and
the fingers are also forming during the sixth week,
the testes become identifiable at this time and some
salivary glands appear. By the sixth to seventh weeks
after conception, the heart is contracting forty to
eighty times each minute.
aorta is developing on the 36th day after conception,
and all the muscle blocks have appeared. The feet and
the thighs become distinct on the 37th day. Finger rays
are visible on the 38th day, when the nose is also formed.
The urinary bladder is developing on the 39th day, and
on the 40th day, the forehead, nostrils, diaphragm and
teeth are beginning to appear.
penis begins to develop on about the 42nd day after
conception, the same day that the beginnings of the
toes are evident.
the eyes and ears are developing rapidly during the
seventh week after conception. At this time, the thumbs,
neck, heels of the feet and all of the fingers are also
and the first hair follicles appear on the 44th day
after conception. On the 46th day, microscopic examination
can identify the child's sex because the ovaries and
testes have differentiated.
cheeks are visible on about the 47th day, when the knees
are also developing. The vagina forms during the 36th
to the 49th days, while the wrist is developing on about
day 48. During the 49th to 51st days after conception,
the arms are longer and bent at the elbows.
buds begin to form during the eighth week after conception.
All parts of the limbs are apparent at this time. In
addition, the fingers and toes have lengthened and are
the 50th day after conception the eyes are heavily pigmented
and the nose looks stubby. The ankles are present on
the 54th day and the major blood vessels of the body
take on their final scheme.
the 56th day, the fingers of both hands are usually
found close to the nose, the muscles of the stomach,
esophagus, and intestines begin to proliferate, and
the face appears quite human. All parts of the arms
and legs are well developed, including the toes. The
primary teeth are at the cap stage.
the end of the eighth week the overwhelming majority
(several thousand) of the body's organs, structures
and systems have already begun to develop. Few, if any,
new structures begin to form after this time. During
the remainder of the pregnancy, development consists
mainly of growth and maturation of the parts of the
body that are already present.
changes that do occur past the eighth week, however,
include the appearance of hair follicles on the eyebrows,
eyelids, upper lip and chin at the end of the second
month. In addition, fingernails and toenails begin to
develop about the tenth week after conception and scattered
rudiments of hair also form at this time. External genitalia
start to appear at the end of this week which will indicate
to the naked eye whether the child is a boy or a girl.
the fourth month, fine palm lines have formed that can
be used to permanently identify the child. Finger, palm
and footprints are never duplicated among individuals.