Fertilization is a whole process that takes place in the body of a woman under favorable conditions. It occurs, as a rule, after sexual intercourse or as a result of artificial insemination.
How does the fertilization of an egg occur in vivo?
The process of conception naturally occurs in several stages:
- Stage of ovulation. In the body of women of childbearing age, unripened eggs in the follicle (a transparent bubble filled with liquid) ripen in one of the ovaries every month. When the period of formation is completed, the follicle is ruptured, and the mature eggs go out. This process is called ovulation, and it usually occurs in the middle of the menstrual cycle. Ovulation is a prerequisite for the fertilization and development of the fetal egg.
- After the eggs have left the ruptured follicle, it turns into a gland of internal secretion called the yellow body. The purpose of the yellow body is the production of hormones of estrogen and progesterone. The latter is needed to thicken the mucous membrane of the uterus, thereby preparing the endometrium to embryo embryo. All described actions affect how the process of fertilization takes place and whether it will take place at all.
- The released egg gets into the abdominal cavity, where it is captured by the fallopian tube. In the fallopian tube, it is located until one of the male spermatozoa gets into it. In this case, the fusion of the egg nucleus with the nucleus of the spermatozoon occurs and fertilization occurs. This period gives an accurate representation of how the fertilization of the egg takes place. It is at this stage of fertilization that genetic information about the future child is laid: sex, hair and eye color, nose shape, etc.
- The time of fertilization of the ovum is about one day after ovulation. During this time, all the above-described processes have time to pass, and depending on the conditions, conception is either carried out or not. If fertilization does not occur in the yellow body and the egg degenerates, the thickened layer of the endometrium is rejected and displayed as menstrual bleeding.
Artificial insemination of the ovum
How artificial insemination occurs depends on the method of reproductive medicine. At the moment there are two most effective programs:
- the IVF program;
- ICSI method.
About how the fertilization of IVF occurs, we can say the following: in the laboratory, male sperm are planted in the female ovum. Further, the process is the same as in the natural environment - from several male cells one penetrates into the egg and, if after a while the division begins, the fertilization period of the egg was successful.
With the ICSI method, a selected strong sperm is injected directly into the egg by a special instrument. With this method, it is possible to completely follow the way in which fertilization takes place.
The processes that occur after fertilization can be divided into several stages:
- Division of a fertilized egg. Within a day after fertilization, the egg is actively divided into cells. Being in the fallopian tube for about three days, it gradually moves along the fallopian tube, where it is attached to the mucous membrane of the uterus.
- The appearance of the embryonic bladder is a blastocyst. Initially, the fertilized egg turns into a heap of cells, gradually moving into a spherical cell cavity. When the blastocyst leaves the protective shell, the third stage - the final stage - begins.
- Implantation and embryo formation. When the blastocyst approaches the endometrium, it is attached to the mucosa. Further, within a few weeks of the growing blastocyst cells, the nerve cells of the child are formed. Otherwise
speaking, an embryo is formed, which after eight weeks of pregnancy already has the full right to be called a fetus.
As in natural conditions, and in reproductive methods, the process of ovulation does not always end in conception. Doctors, too, not in all situations can answer the question of why fertilization does not occur. The reasons are many and they are different in each case. In this article, we described the mechanism of how the egg is fertilized, and tried to answer the questions, how much time and how long fertilization takes place, without setting out to explain the reasons for failed attempts at fertilization.