Great life begins – when sperm meets egg… The process of sperm and egg union is called fertilization or conception, and conception is the beginning of pregnancy. During sexual intercourse, a man emits about 200-400 million sperm each time, most of which are expelled from the vagina with the semen, while a small percentage of sperm move forward by tail wagging, successively passing through the cervical canal, the uterine cavity and finally reaching the terminal point – the abdomen of the fallopian tube, where they wait to unite with the egg. The fastest time for sperm to reach the fallopian tube from the vagina is just a few minutes, the latest 4-6 hours, and usually 1-1.5 hours. The sperm are blocked by cervical mucus and engulfed by white blood cells in the uterine cavity, and only a few dozen to one or two hundred sperm reach the fallopian tubes. The spermatozoa are incubated in the female reproductive cavity for a period of time before they are able to fertilize the egg, a process called sperm capacitation. In women of reproductive age, the ovaries expel one mature egg per month, about 14 days before the next menstrual period. Immediately after discharge from the ovary, the egg is sucked into the fallopian tube by the umbrella of the fallopian tube and is in the abdomen of the tube in order to await the arrival of the sperm. The sperm can survive in the fallopian tube for 1-3 days and the egg for about 1 day. If intercourse takes place within a few days before or after the woman’s ovulation day, the sperm and egg may meet in the abdomen of the fallopian tube. Only one sperm enters the egg and then a new cell is formed, which is called a fertilized egg, a process called fertilization. The fertilized egg draws nutrients and oxygen from the fluid secreted by the fallopian tubes and continues to undergo cell division. At the same time, the fertilized egg gradually moves toward the uterine cavity and by the time it reaches the uterine cavity 3-4 days later, it has developed into an entity with multiple cells shaped like a mulberry, hence the name mulberry embryo. The mulberry embryo continues its cell division in the uterine cavity to form a blastocyst, which enters the endometrium about 6-8 days after fertilization, a process called implantation or implantation. After implantation, the fertilized egg gradually develops in the uterine cavity. 3-8 weeks after fertilization, the fertilized egg develops into an embryo, and after 9 weeks, it develops into a fetus.