The embryo usually travels in the fallopian tube for 1 week before entering the uterus. Pregnant mothers basically experience ovulation every month before conception. After ovulation, the fallopian tubes pick up the egg, which then enters the fallopian tubes. If it encounters sperm in the fallopian tube, fertilization occurs and the fertilized egg travels within the fallopian tube for about 1 week to enter the uterus. If you are a pregnant woman with regular menstruation, normal ovulation and normal conception, basically the embryo will enter the uterus about 21 days after menopause, counting from the beginning of menopause. Therefore, the embryo enters the uterus basically from the first day of the last menstrual period, and it will enter the uterus around 21 days.