The basic conditions for fertility are: the presence of normal sperm and eggs in both sexes; the ability of sperm and eggs to meet in the female reproductive tract; and the successful fertilization of the egg in the uterus. Azoospermia or oligospermia, low sperm motility and deformed sperm can reduce or deficient the ability to fertilize the egg; non-ovulation, sparse ovulation or ovulation disorders can reduce or deficient the ability to conceive. The main reason that affects the meeting of sperm and egg in the female reproductive tract is obstruction or dysfunction of the fallopian tubes, followed by cervical factors and immune factors that prevent sperm from entering the uterus and fallopian tubes from the vagina smoothly. Too little or too sticky cervical mucus prevents sperm from moving through the cervical canal. If the endometrium is too thin to accept the seed and supply sufficient nutrients, the seed cannot take root and germinate and cannot conceive and develop, just like a seed planted in the soil. Common clinical causes of infertility include: 1. male factors: azoospermia, oligospermia, low sperm motility, deformed spermatozoa, pus spermatozoa, and semen indigestion, etc. 2. Fallopian tube factors: blockage, incompetence and dysfunction of fallopian tubes. In the past, it was mostly caused by inflammation, but in modern society, the proportion of women with endometriosis has increased, and the proportion of tubal obstruction, incompetence and dysfunction caused by this has increased greatly. 3. Ovulation disorders: non-ovulation, ovulation sparingly, or ovulation dysfunction (small follicular ovulation disorder or luteinization of unruptured follicles). 4, luteal insufficiency: progesterone produced by the corpus luteum can increase BBT. In luteal insufficiency, BBT high temperature phase is less than 11 days or high temperature phase is unstable, temperature difference is small, climbing-like rise, slow rise and early fall, mid-luteal progesterone value is 16-48 nmol/L. If the corpus luteum is not well formed, it can affect fertilized egg implantation and cause infertility. The above mentioned patients with luteinization of unruptured follicles are mostly accompanied by luteal insufficiency. 5. Cervical and immune factors: due to too little and too thick cervical mucus, the cervical mucus conditions during ovulation are not conducive to sperm penetration into the uterine cavity, which is an important cause of infertility. Endometriosis: severe endometriosis often has structural changes in the pelvis, forming pelvic adhesions, tubal and ovarian adhesions and involvements, which affect the egg collection and ovulation function of the fallopian tubes, while ovarian chocolate cysts affect ovulation; infertility caused by mild endometriosis patients may be related to changes in the pelvic environment such as cellular and humoral immunity and endocrine function. 7.Other factors: abnormalities or functional abnormalities of the reproductive tract cause difficulties or failures in normal reproduction. 8. Combined factors: multiple causes of infertility.