The World Health Organization defines infertility as the failure of a couple of reproductive age to conceive after having normal, regular sex for at least one year without using any contraception. The incidence of infertility is increasing year by year, and infertility has become a worldwide medical and social problem, and is one of the important diseases that endanger human reproductive health in the 21st century. The causes of female infertility are many and complex, mainly including the following major categories: 1. age factors Age is an important factor that independently affects female fertility. As we grow older, it may be due to a decrease in the number and quality of eggs, a decrease in the fertilization ability of eggs and the ability to grow embryos, and an increase in the chance of chromosomal abnormalities, making the chances of successful conception decrease year by year. Irregular menstrual cycles or amenorrhea are common manifestations of abnormal ovulatory function. 15-21% of female infertility patients have ovulatory disorders. Normal ovulation depends on the dynamic balance of hormones in the hypothalamic-pituitary-gonadal axis, so abnormal ovulation is a manifestation of the abnormal function of the above system. Tubal factors The peristalsis of the smooth muscle of the fallopian tube, the oscillation of the epithelial cilia and the patency of the fallopian tube are the necessary conditions for natural conception, and both infectious and non-infectious causes of tubal infertility can lead to infertility. 4, uterine factors Uterine infertility mainly includes the following conditions, congenital uterine agenesis, congenital uterine malformation, uterine fibroids, adenomyosis, endometritis, endometrial polyps, endometrial atypical hyperplasia, etc., which prevent sperm from moving up and fertilized eggs from being laid and planted. 5. Endometriosis and infertility 30-58% of infertility patients are combined with endometriosis, which is closely related to infertility. Endometriosis causes pelvic adhesions, tubal obstruction or prevents the fallopian tubes from transporting eggs, interferes with ovarian endocrine function and ovulation, and affects sperm-egg union and embryo implantation. Lower genital tract and cervical infertility Abnormal development of the vulva and vagina, as well as trauma and surgical scar narrowing, can affect the upward movement of sperm and the union of eggs. Immunological infertility There are complex immune reactions in all aspects of natural conception, and the neuroendocrine system and the immune system influence reproductive endocrine and regulate the fertility process through the interaction of peptide hormones, neurotransmitters and cytokines. Diagnosis of immune infertility begins with the exclusion of other known factors of infertility, including anatomical, tubal, endocrine, and genetic factors. 8. unexplained infertility The incidence of unexplained infertility in infertile couples is 10-20%. The diagnosis of unexplained infertility should at least meet the following criteria: normal semen analysis in the male partner, ovulation in the female partner, normal uterine cavity, and bilateral patency of both fallopian tubes under laparoscopy.