Artificial insemination is an assisted reproductive technique in which treated semen is artificially injected into the female reproductive tract to unite the sperm with the egg in order to achieve a female pregnancy. The treated semen is injected into the uterine cavity of the female partner with a special fine tube. The spermatozoa have to swim from the uterine cavity into the bilateral fallopian tubes, reach the abdominal part of the fallopian tubes (the widest part) and meet the eggs discharged from the ovaries, fertilize and form a fertilized egg, i.e. embryo, which then develops in the fallopian tubes while swimming away into the uterine cavity for implantation. After the male partner’s semen is removed and treated with washing and antigens, it can increase the density of motile sperm, reduce or remove prostaglandins, immunologically active cells, anti-sperm antibodies and bacteria and debris from the seminal plasma, reduce the viscosity of semen, and promote sperm capacitation and improve sperm fertilization. In layman’s terms, this means freeing the sperm from unfavorable factors (e.g. semen analysis suggesting non-liquefaction, ability to remove seminal plasma and other impurities) so that the really good sperm (fast linear moving sperm and sperm with good morphology) can stand out and thus make better use of their abilities. Depending on the source of the sperm, artificial insemination includes both husband sperm artificial insemination and donor sperm artificial insemination (sperm banking). Artificial insemination with husband’s sperm (AIH) is the use of the husband’s semen, and artificial insemination by donor sperm (AID) is the use of someone else’s semen (sperm bank) artificially inseminated with sperm donated by eligible volunteers. There are three types of insemination according to the method of insemination: intrauterine (IUI), intravaginal (IVI) and intracervical insemination (ICI). Compared with IVF-ET, IUI is simple, safe, inexpensive, and less damaging to the patient, with a pregnancy rate of 10%-15%. So, those infertile couples can choose the IUI method: there are five main categories as follows: 1. male semen abnormalities: low semen volume, long liquefaction time, low sperm count, poor viability and high malformation rate; 2. sexual intercourse abnormalities that prevent semen from entering the female reproductive tract. Male ejaculation disorder: such as impotence, premature ejaculation, non-ejaculation, retrograde ejaculation, etc.; male genital malformation: hypospadias, penile flexion malformation, etc.; female vaginal and cervical stenosis, vaginal spasm, etc.; 3. Cervical factor infertility: such as thick cervical mucus, cervical inflammation, etc.; 4. Immunological infertility: the male or female partner has anti-sperm antibodies; 5. Unexplained infertility: the couple has normal sexual life and has not been pregnant for more than 1 year. 5. Unexplained infertility: It refers to a couple who have normal sexual intercourse and have not been pregnant for more than one year, and the tests of both men and women are normal. It accounts for about 10% of the total infertility population. If these indications are met, the following prerequisites must be met in order to choose artificial insemination for pregnancy: 1. The woman must have patent fallopian tubes. During normal conception, the ovaries need to ovulate through the fallopian tubes and meet the sperm entering the body. IUI treatment only delivers the sperm into the female reproductive tract, but it still has to pass through the fallopian tubes to meet the egg. If the fallopian tubes are incompetent, the sperm and the egg are like a cowherd and a weaver, looking at the river but unable to meet each other, and it is impossible to conceive. If the tubes are not open, the function of the fallopian tubes will be affected and the success rate of artificial insemination will be reduced. Therefore, the woman must have a hysteroscopy or an iodine oil imaging of the fallopian tubes before insemination to clarify the patency of the fallopian tubes. 2. The female partner must have mature follicles discharged Under the influence of sex hormones in the body, a woman will ovulate once a month during the intermenstrual period, i.e. mature follicles are discharged from the ovaries. Only when there is a mature egg is it possible for the sperm and egg to meet and the conditions for conception to occur. 3. The male sperm quality needs to meet certain standards Male oligospermia can be treated with artificial insemination, but after the sperm is processed in the laboratory: IUI: the total number of PR must not be less than 10×106 ICI: the total number of PR must not be less than 10×106 Only a sufficient number of sperm enters the female body to have a chance of conception.