After fertilization, the egg occurs, it begins to move slowly along the tube toward the uterus. The motion was carried by the walls of the oviduct muscle contractions and variations of cilia covering the pipe inside. It moves the egg is not very fast and reaches the uterus as 8-10 days after fertilization.
Gradually, the embryo begins to produce specific enzymes that destroy the endometrium. The interior is the erosion which is attached and the fetus. This process is called nidatsiey. The embryo, of its outer covering villi, gradually comes into contact with blood vessels in the body of a woman. Previously, he provided food substances in the egg, then this is now done through the mother.
After his departure for blood to flow of nutrients and oxygen. complete the accession process of the embryo to the uterine wall is completed in 12-14 days after fertilization. Nidatsiya embryo depends on the speed of his promotion to the uterus. During the movement of eggs through the pipe gradually form a special layer of high, then the enzymes are produced, thereby destroying the membrane lining of the uterus and attach to the wall.
If the motion is too fast, then this layer is not the time to train, so the embryo can not attach to the uterus. Following the miscarriage occurs.