Implantation of the fetal egg

After the spermatozoon reaches the uterinepipes, he meets with the egg, destroys its protein shell and penetrates inside. This is the way in which fertilization takes place, which becomes the beginning of the development path of the embryo. After the confluence of father's and mother's materials, a fetal egg is formed - a future child. Fruit egg passes through certain stages of its development, which are characterized by quantitative and qualitative changes. But in order to further development of the fetal egg is possible, it needs a nutrient medium from which nutrients will be supplied during the next nine months. This environment becomes the uterus.

So, the fetal egg in the fallopian tubes descendsdirectly into the uterus. This is due to the presence of microscopic villi inside the fallopian tubes, which promote the fetal egg. If the fallopian tubes have pathologies (adhesions, bends), the implantation of the fetal egg becomes much more complicated, since the path to the uterus becomes problematic. In this case, the fetal egg can linger in the fallopian tubes and attach there. This phenomenon is called ectopic (tubal) pregnancy and requires medical intervention.

Usually with a normal structure of the fallopian tubesthe fetal egg enters the uterus within four days. At this time, it is in the morula stage, and when it enters the uterus, it is in the blastocyst stage. This stage is characterized by the fact that the fetal egg is ready for new changes. Blastomers begin to form an embryoblast - the part from which the embryo will develop in the future, and the second part of the cells - trophoblast - from them the nutrient shell for the egg will form (the most productive part of the trophoblast will later turn into a placenta).

At this stage, implantation of the fetal egg onlybegins. Under the influence of hormonal changes, the uterus prepares for it. After the follicle burst, a yellow body was formed, which, to a large extent, secretes progesterone and, to a lesser extent, estrogen. Progesterone signals the mucous membrane of the uterus about the need to prepare its layer. First of all, the quality of the endometrium changes in the uterus - it is called the decidual membrane during pregnancy. What is the difference between a new endometrium? The main feature of such an endometrium is the accumulation on its thickness of biologically active compounds that nourish the embryo. This glycogen, mucopolysaccharides, lipids, salts and trace elements, enzymes, immunoglobulins - all of them are simply necessary for the implantation of the fetal egg to continue its full development of the fetus. In other cases, when there are defects in the endometrium and its functions, women for a long time can not become pregnant, and sometimes even become barren.

With a normal endometrium, implantation of the fetuseggs lasts about two days. During this time at the place of attachment (nidation) the blood vessels expand, the endometrium thickens. Such changes indicate that the uterus is ready to take the blastocyst. When immersing a fetal egg in the thickness of the endometrium, it seems to be enveloped by villi in the uterus. Sometimes this attachment can be accompanied by a slight bleeding, which can be mistaken for untimely started menstruation. However, the amount of blood is extremely small - a few drops or a small spot, after which such a "bleeding" stops. Implantation of a fetal egg, the signs of which are not felt by a woman, only in this way makes itself felt, since it occurs in the middle of the cycle, after ovulation, and before the onset of menstruation is still far away. If women follow their cycle and know the time of ovulation, then with a high probability they can hope for the onset of pregnancy. Only in a small number of women implantation of the fetal egg, the sensation of implantation is somehow manifested. Sometimes tingling, nausea, feeling of heaviness is felt. However, they are caused not by implantation itself, but by hormonal changes occurring in the body.