Month by month embryo development
Magic within 270 days
The course of human embryo development is a real wonder. Imagine, just within 270 days more than 200 million cells are developed out of only one cell. And the little embryo, which is initially invisible and could be discerned only through microscope, grows half a meter in height.
Every process of its development runs in a step by step mode, following the rules of nature like everything else in the universe.
The first step: the moment of ovum fertilization till the end of the second week of fetus`s life in the mother`s womb. The second step: development of the fetus from the beginning of the third week through the eighth week. In this period some important changes happen to the fetus – the embryo starts to look like human and the formation of all vitally important organs is commenced. At the end of the second step the embryo could be called a fetus. The third step is the final one. It starts from the third month and culminates with baby birth. The most interesting thing about the human fetus is resemblance of its main development processes to those of vertebrates. There are only a few differences between human fetus and that of other representatives of earth`s fauna which allow to trace the development stages of human fetus. Thus only human fetus develops inside mother`s womb within 270 days, which equals to 10 lunar months.
The first trimester of pregnancy
The first trimester or the first 13-14 weeks is the most important period in the development of a baby, since it is the period when his all internal organs start to form.
In the first 7 days after fertilization the ovum cell starts to divide. Even if this process runs without pathologies, it does not mean successful pregnancy unless ovum implantation occurs. That is why the period from the 7th through the 9th day are considered the most crucial.
In case when the ovum did not get fastened well enough or got attached too high or low, it could be a risk pregnancy. It means that the baby would be developing normally, but the threat of miscarriage will be impending for a rather long time.
Another anomaly could be considered implantation of the ovum in any of the uterine tubes. In such a case the fertilized ovum does not get enough nutrition, since there are too few vessels there. Moreover, maintenance of such a pregnancy poses hazard to woman`s life.
The next important period of pregnancy is the 2nd -through the 9th week. Any deviation in the development of the embryo in this period usually leads to spontaneous abortion. Also pay special attention to your health in the 11th-13th week, since it is time when a new stage of fetal development starts.
Now we see how important the first trimester is and how little the successfulness of this period depends on the mother. It is time when the nature by natural selection promotes birth of healthy children. Nonetheless in most cases when the mom-to-be does not abuse alcohol, smoking or some medicines and is in good health, she has greater chances to avoid miscarriage and her pregnancy would proceed without any abnormalities. First of all normal pregnancy is associated with the correct chromosome number in the egg cell.
The second trimester of pregnancy
During the second trimester the fetus continues to develop. During this period it would grow considerably. Now your pregnancy would be noticeable to others, since your stomach grows in size quite quickly. In this period the baby makes more coordinated moves, the number of which may reach 600 during one day. The baby would be most active in the 6th month of pregnancy.
By the end of the second trimester the fetus is already viable. But if the baby is born at this period, he would be able to make the first breath and cry, but unfortunately the baby is still too weak to survive.
The third trimester of pregnancy
During the third trimester of the pregnancy quite a few changes happen in the life of the baby. Most of his organs have already formed and some of them even function. Now he needs to gain some weight and grow in height. The last period of pregnancy is the most difficult for the mother. It is a period when most of complications and ailments occur. They include leg swelling, varicose veins dilatation, backache, heavy breathing, etc.
In this period the mom gets exhausted very quickly and need to rest more frequently. She is no longer able to perform same volume of activity she used to.