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Zygote
This is an image of an egg recently fertilized by a sperm, creating a zygote. -
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Nine Months– 3 Trimesters
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First Trimester
Week 1: When the sperm fertilizes an egg, a zygote is created. After about three days, this zygote has turned into a morula, and by the sixth day it is a blastocyst ready for implantation of the uterus.
Weeks 2-5: Brain, circulatory system (heart + blood cells), spinal cord, digestive system, bones, limbs, nervous tissue, eyes, nose, kidneys, and lungs develop.
Weeks 6-8: Hands, feet, digits, hair, eyelids, and testes or ovaries form. Brain waves and urine are present for the first time. -
Embryo Picture
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Embryo
Weeks 2-8 -
First Trimester Picture
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Fetus
Weeks 9-38 (birth) -
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Second Trimester
The second phase is the most relaxed; all the sickness and fatigue that felt in the first trimester passes. During week 13 is when the second trimester normally starts. By week 14 the baby will weigh about 40 grams. In this trimester the bones continue to form, and the hair is growing. Between the 18th and 22th week of pregnancy, an ultrasound can determine the fetus' sex. By the end of this trimester the baby will start to hear, weighing 200 grams. -
Second Trimester Growth
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Second Trimester Growth Picture
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Fetus at 24 Weeks
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Third Trimester
By the third trimester the fetus' eyes are open and they have created eyelashes. Also, their bones are fully formed, but are still pliable; bone marrow forms red blood cells. In the late third trimester, the baby's toenails become visible and it has more hair on it's head. The fetus begins to practice breathing. It is growing expoentially and absorbing minerals. By the last week the baby is chubbier and it has descended into the mother's pelvis. -
Third Trimester Growth
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Week 36 Picture
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Third Trimester Picture
