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Period: to
Prenatal Development
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1st month
-The dividing fertilized egg moves down the fallopian tube toward the uterus.
-At about 5 days after fertilization, the cluster of dividing cells enters the uterus.
-At about 8–9 days after fertilization, the cluster of cells (now called a blastocyst) attaches to the lining of the uterus. -
2nd month of pregnancy
-The placenta begins to form.
-The brain and spinal cord begin to form.
-The tissues that will form the heart begin to beat. The heartbeat can be detected during an ultrasound exam at about 6 weeks of pregnancy. -
3rd month pregnancy
-Buds for future teeth appear.
-Fingers and toes start to form. Soft nails begin to form.
-Bones and muscles begin to grow.
-The intestines begin to form.
-The backbone is soft and can flex.
-The skin is thin and transparent.
-The hands are more developed than the feet.
-The arms are longer than the legs. -
4 month pregnancy
Eyebrows, eyelashes, and fingernails form.
Arms and legs can flex.
External sex organs are formed.
The placenta is fully formed.
The outer ear begins to develop. -
5th month pregnancy
The sucking reflex develops. If the hand floats to the mouth, the fetus may suck his or her thumb.
The skin is wrinkled, and the body is covered with a waxy coating (vernix) and fine hair (lanugo).
The fetus is more active. You may be able to feel him or her move.
The fetus sleeps and wakes regularly.
Nails grow to the tips of the fingers.
The gallbladder begins producing bile, which is needed to digest nutrients. -
6th month pregnancy
Real hair begins to grow.
The brain is rapidly developing.
The eyes begin to open.
Finger and toe prints can be seen.
The lungs are fully formed but not yet functioning. -
7th month pregnancy
-The eyes can open and close and sense changes in light.
-Lanugo begins to disappear.
-The fetus kicks and stretches. -
8th month pregnancy
With its major development finished, the fetus gains weight very quickly.
Bones harden, but the skull remains soft and flexible for delivery.
The different regions of the brain are forming.
Taste buds develop, and the fetus can taste sweet and sour. -
9th month pregnancy
The fetus drops lower into the pelvis.
More fat accumulates, especially around the elbows, knees, and shoulders.
The fetus gains about 1/2 pound per week during this last month of pregnancy.
