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1st Trimester:
Pregnancy is broken down into weeks, and is divided into three equal parts
called trimesters. Full term pregnancy is considered 40 weeks and an
infant delivered before the 37th week completed is considered premature.
Premature infants may have problems with their growth and development, as
well as difficulties in breathing and digesting. Pregnancy is counted from
the first day of a your last period. This means that at conception, the
unborn baby is already considered two weeks old. Also see BabiesDirect
month to month diary to learn about the emotional and physical journey
of pregnancy.
Fetal Development
2 weeks
- The sperm and egg join in the fallopian tube and fertilization has
occurred. The baby begins to form from a single fertilized egg to a
cell that has divided itself and is
 now multiplying rapidly.
Forty-six chromosomes combine, which pre-determine all of a person's
physical characteristics. Thirty hours later the developing embryo is
still rapidly dividing and it floats down from the fallopian tube and
towards the uterus. If the embryo doesn't get to the uterus and stays is
the fallopian tube, the result is
Ectopic
pregnancy. Make sure you refer to our nutrition
section as it is VERY important.
3 weeks
- Now the when the developing embryo is in the
uterus, it searches for a nice place to implant. When one is found the
embryo burrows beneath the surface of the uterus. During these early weeks
of life blood cells are being produces by the yolk sac. The unborn baby is
only one-sixth of an inch long, but is rapidly developing. The backbone,
spinal column, and nervous system are forming. The kidneys, liver, and
intestines are taking shape.
What
Tests will Doctors Run
at this point in my Pregnancy?
4 weeks
- At week four, you might begin to suspect you're
pregnant since the embryo produces hormones which stop the mother's
menstrual cycle. The fertilized egg, now called a
blastocyst, is a fluid-filled cluster of cells, still multiplying madly. It is
attached to
 the uterus wall and divides into two parts. The half attached
to the uterine wall becomes the
placenta
, the vessel-filled support system that nourishes the developing life, and
the other half will become the baby. Nerve growth begins when a sheet of
cells on the back of the
embryo
folds in the middle to form a tube, which will become the future spinal
cord. At one end tube enlarges to form the brain's major sections. The
amniotic fluid
that cushions the
fetus
begins to form. Make sure you refer to our nutrition
section as it is VERY important.
5 weeks
- At this time the embryo is still size of
a raisin. Low on the sides of the head are two folds of tissue that will
become the ears. Although not completely developed, all the major body
organs and systems are formed. The neural tube enlarges into three parts,
that will soon to develop to become a very complex brain. Also the
placenta begins functioning, known as the chorionic villi and the
umbilical cord, through which the baby will receive nourishment and oxygen. The spine
and spinal cord grows faster than the rest of the body at this stage and
will give the appearance of a tail. This disappears as the baby continues
to grow.
 6 weeks
- On the 26th day the embryo's tiny heart begins
to beat. The embryo itself is about a 1/4 inch long. Other major organs,
including the kidneys and liver, have begun to develop, and the neural
tube, which connects the brain and spinal cord, closes. The physical
sensations of pregnancy start--nausea, fatigue, sore breasts and frequent
urination.
7 weeks
- The embryo's hands and feet are shaped like
paddles, but the fingers are beginning to take shape. The embryonic tail
has almost disappeared. The pituitary gland is also forming and the
fetus
is beginning to grow muscle fibers. The heart has divided into the right
and left chambers and is beating about 150 beats a minute which is about
twice the rate of an adult. The baby's facial features are visible,
including a mouth and tongue. The eyes have a retina and lens. The major
muscle system is developed, and the baby starts to practice moving. The
baby has its own blood type and the blood cells are produced by the liver
now instead of the yolk sac.
8 weeks- The unborn baby is now called a fetus. The fetus is protected by the amniotic sac and filled
with fluid. Inside the child swims and moves gracefully. The fetus is now
about 3/4 inches long. The arms and legs have lengthened.
During this time
of development, the baby's head appears much larger than the body because
the brain is growing very rapidly. Brain waves can now be measured. The
teeth and the palate are beginning to form and the larynx is developing.
Through its parchment-thin skin, the baby's veins are clearly visible. By
the eighth week the ears begin to take shape.
9 weeks
- Though the fetus is constantly moving, you
won't be able to actually feel fetal movement for several more weeks. All
of the organs, muscles, and nerves are in place and beginning to function.
As the hands and feet develop fingers and toes, they lose their
paddle-like look, and the touch pads on the fingers form. Make
sure you refer to our nutrition
section as it is VERY important.
10 weeks
- The
fetus weighs about 1/3 of an ounce. The heart is almost completely
developed and very much resembles that of a newborn baby. An opening the
atrium of the heart and the presence of a bypass valve divert much of the
blood away from the lungs, as the child's blood is oxygenated through the
placenta. The eyelids have fused shut and won't open again until week 27.
The wrists and ankles have formed and the fingers and toes are clearly
visible. Genitals have begun to from, but it is too early to tell the sex
of the fetus. By this week of the pregnancy the
placenta
has developed enough to support most of the critical job of producing
hormones
.
 11 weeks
- The vital organs--the liver, kidneys, intestines,
brain and lungs--are fully formed and beginning to function, while the the
head is almost half the length of the entire body. The
fetus
is only about 2 inches long and weighs less than a half ounce but it is
busy moving and kicking.
12 weeks
-
Vocal chords are complete, and the baby can
and does sometimes cry silently. The brain is fully formed, and the baby
can also feel pain. The fetus may even suck his thumb. The eyelids now
cover the eyes, and will remain shut until the seventh month to protect
the delicate optical nerve fibers. The hair is on the head and the fingers
and toes have developed soft nails. The kidneys are developed and begin to
secrete urine.
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