Almost immediately after conception, a woman's body continuously and in increasing concentrations produces the pregnancy hormone - human chorionic gonadotropin (hCG). It is he who leads to various changes in the body of the expectant mother, causing headaches, morning sickness and much more. These signs may begin to appear about eight days after ovulation or from the moment a fertilized egg implants in the lining of the uterus. It is important to know that a period of 8-10 days is the approximate time for implantation of the embryo; this period is individual for each woman. Sometimes it can lengthen, and the first signs will appear later. In addition, not all women in general may experience malaise or other signs associated with an increase in the level of the pregnancy hormone. This does not mean at all that conception did not occur, and that the embryo does not develop. Do not worry ahead of time, the most key signs will be a delay in menstruation and a subsequent positive pregnancy test, and not various sensations.