The conditions necessary for the establishment of a normal pregnancy are: 1) ovulation in the female; 2) patent fallopian tubes and no adhesions in the pelvis; 3) a normal uterus with no malformations; 4) normal semen in the male partner and sexual intercourse during ovulation; The above diagram shows that: after ovulation of the ovary the oocyte enters the fallopian tube and unites with the sperm in the abdomen of the fallopian tube. The united embryo starts to undergo oocytosis, forming 2 cells, 4 cells, 8 cells, etc., in The embryo starts to undergo oogenesis, forming 2-cell, 4-cell, 8-cell, etc., and moves towards the uterus at the same time as the oogenesis, and then implants in the uterine cavity 5-6 days after the sperm-egg union. If the implantation is successful, an increase in HCG concentration can be detected in the blood and urine about 1 week after implantation, confirming the pregnancy.