Medically speaking, the gestation period is counted from the first day of the last menstrual period. Fertilization of a mature egg is the beginning of pregnancy, just pregnant 1~7 days, if it means 1~7 days after coitus, usually no symptoms.
On the first day of pregnancy, the sperm enters the fallopian tube, passes through the zona pellucida of the oocyte membrane, and combines with the egg to form a fertilized egg. The formation of a fertilized egg marks the birth of a new life, and the whole process takes about 24 hours.
At this time, the embryo is in the cellular stage, running in the fallopian tube toward the uterine cavity, in the process of running, through mitosis fertilized egg will become bigger and bigger, after fertilization of the 6th to 7th day, the blastocysts will be implanted in the uterine lining, known as the fertilized egg implantation.
Within 1 to 7 days of pregnancy, the embryo and the mother have not yet established blood circulation, so chorionic gonadotropin cannot be detected in a woman’s blood, and the woman usually has no symptoms.