The implantation usually begins about seven days after coitus.
Sperm enters the female reproductive tract and meets and combines with the egg to form a fertilized egg, which usually takes 24 hours. The fertilized egg will reach the uterine cavity under the action of the fallopian tubes, and begins to lay in the uterine lining about seven days after fertilization.
Fertilized egg formation marks the birth of new life. Fertilized egg implantation is an important process in the early stages of embryo formation. About seven days after fertilization, the fertilized egg begins to bed in the uterus. At this time, the blastocyst and the uterine lining must develop synchronously and function harmoniously, and the uterus has a very short sensitive period to allow the fertilized egg to bed.
On the day after implantation, the embryo secretes chorionic gonadotropin, which can be expressed in a woman’s blood, and this is when a blood test is done to find out if she is pregnant.