1. Fertilization of the egg- This is the most important event because it is the beginning of the pregnancy journey.
2. Implantation of the embryo into the uterus wall- this is very important because correct placement of the embryo can mean a successful pregnancy but incorrect placement of the embryo into the fallopian tube can result in a failed pregnancy. This begins one week after fertilization and ends about two weeks after fertilization
3. Hormone levels increasing- The hormone levels in a pregnancy are very important for many reasons the hormone hCG (human chorionic gonadotropin) supports the pregnancy by ensuring production of progesterone until the placenta is fully formed. This is also the hormone that is detected on pregnancy tests. Progesterone is produced by the placenta and it functions to inhibit contracting of the uterus by inhibiting smooth muscle. This affect on smooth muscle also shows in other areas of smooth muscle in the woman’s body. Estrogen is also produced by the placenta and it is characterized by an increase in uterine blood flow and a woman’s increased emotional sensitivity. Pro-lactin is another hormone that allows for lactation postpartum. These hormone levels begin changing when the embryo implants and do not stop fluctuating until after the baby is born
4. Formation of what will become the amniotic cavity- significant because this is what will surround and protect the baby from activity by the mother and it begins at 7-12 days after fertilization
4. Formation of what will become the amniotic cavity- significant because this is what will surround and protect the baby from activity by the mother and it begins at 7-12 days after fertilization
. Formation of future placenta and umbilical cord- important because this is what will nourish the baby for development and rid it of wastes. The umbilical cord will serve as a blood exchange route. This begins at about 13 days after fertilization
6. The beginning of gastrulation- significant because the cells migrate to areas to become tissue layers known as the primary germ layers and are called the ectoderm which becomes the skin, lining of oral cavity and the nervous system. The mesoderm becomes the skeleton, muscular system, dermis of skin, cardiovascular system, reproductive system and digestive system among others. The endoderm becomes the lining of the digestive and respiratory tract and other glands associated with these systems. This happens at 13-16 days after fertilization
7. The heart starts to beat- significant because it shows that this is a human being even at this early stage of development. Occurs at 23-25 days after fertilization
6. The beginning of gastrulation- significant because the cells migrate to areas to become tissue layers known as the primary germ layers and are called the ectoderm which becomes the skin, lining of oral cavity and the nervous system. The mesoderm becomes the skeleton, muscular system, dermis of skin, cardiovascular system, reproductive system and digestive system among others. The endoderm becomes the lining of the digestive and respiratory tract and other glands associated with these systems. This happens at 13-16 days after fertilization
7. The heart starts to beat- significant because it shows that this is a human being even at this early stage of development. Occurs at 23-25 days after fertilization
8. Formation of future brain and spinal cord- both crucial to development and life of the baby. Begins at 17-19 days after fertilization
9. Limb bud formation- this is the beginning of the embryo looking more like a human being. Begins at 31-35 days after conception
10. The pituitary gland starts forming- significant because this gland will eventually send the message to the uterus to start contracting. Begins at 42-44 days
11. Formation of the gonads- significant because these will soon begin to show outward signs of the sex of the baby! Begins at 48-51 days
9. Limb bud formation- this is the beginning of the embryo looking more like a human being. Begins at 31-35 days after conception
10. The pituitary gland starts forming- significant because this gland will eventually send the message to the uterus to start contracting. Begins at 42-44 days
11. Formation of the gonads- significant because these will soon begin to show outward signs of the sex of the baby! Begins at 48-51 days
There are so many important events in a pregnancy it is difficult to narrow it down to ten, I feel that the most crucial development happens in the first trimester so I kept my events narrowed down to those months.
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