Main event: implantation.
Within about three days from the moment of fertilization of the egg, the morula reaches the uterus and penetrates it. Now the group of cells that continue to divide is called a “blastocyst.” It can be seen even with the naked eye.
The blastocyst floats freely in the uterine cavity for about two to three days, growing tiny protrusions on its surface that will help it attach to the uterine mucosa. It is surrounded by amniotic fluid - a biologically active environment that reliably protects the child and is a source of nutrients for him throughout pregnancy.
By the seventh day after fertilization of the egg, the blastocyst is ready for “implantation” - this is the name given to the process of attachment of the fertilized egg to the wall of the uterus. It lasts approximately two days.
The blastocyst attaches to the walls of the uterus in the optimal place from the point of view of pregnancy development. This usually occurs in the area of the front or back wall.
Already by the time the egg begins to descend into the uterine cavity, the blastocyst is divided into two parts.
One part, the inner group of cells, forms the embryoblast, which later becomes the embryo.
The outer group of cells serves as a nutrient membrane - trophoblast, part of which goes to the beginning construction of the placenta.
The placenta will nourish and protect the fertilized egg, embryo, fetus and finally the unborn child throughout the entire intrauterine period of development.
Once implantation has occurred, conception can be considered complete. It is the fact of implantation of a fertilized egg in the uterus and all subsequent hormonal processes in the female body that prevent the arrival of the next menstruation.
Women who know their body well or have increased sensitivity (both physiological and psychological) can already notice the first signs of pregnancy at this stage.