1. Detailed medical history of the female and male partner, including history of infertility, examination and treatment, history of surgery, general physical examination and examination of reproductive organs, etc. 2.Chromosome, hepatitis B five items, hepatitis C antibody, HIV antibody, syphilis serology, ABO and RH blood group, AsAb; TORCH, liver function, kidney function, coagulation function, chest X-ray, electrocardiogram, TCT, blood sedimentation, blood routine, urine routine, white belt routine, cervical secretion mycoplasma, chlamydia, gonococcal examination for the female partner. 3.Pelvic ultrasound examination and measurement of basal endocrine hormones FSH, LH, E2, PRL and T on the 2nd to 4th day of menstrual cycle. 4.Hysteroscopy or diagnostic scraping: hysteroscopy or diagnostic scraping is required for those with uneven endometrial echogenicity, abnormal menstruation and suspected uterine cavity lesions; for those who failed in the first IVF, hysteroscopy is recommended to understand the uterine cavity before the second assisted conception treatment. 5. Semen examination of male partner: routine semen test analysis, morphological and functional examination of sperm if necessary. 6. Tubal examination records are required for tubal factor infertility. 7.Introduce the general process, cost, complications and possible dangers of IVF-ET to the infertile couple, and sign the relevant informed consent form and consent form for multiple pregnancy reduction. 8.Review the marriage certificate, ID card and family planning certificate of both parties, and keep the copy in the medical record. 9.Patients with PCOS, low ovarian function and irregular menstruation can be pre-treated with drugs such as MaFuLong, Daine-35 and Metformin according to the patient’s specific condition; routine pre-conception application of folic acid is started until the third month of pregnancy. Pre-operative examination prescribing principle: perfect all examinations according to the contents required by the routine pre-operative examination. After determining to carry out assisted conception treatment, first of all, basic endocrine, blood group and chromosomal examinations should be carried out as early as possible according to the time requirements; chest X-ray and cervical cytology examinations should be completed one cycle earlier; various examinations for infectious diseases should be completed in the month of entering the treatment cycle, so as to reduce patients’ repeated multiple visits and avoid the phenomenon of expired laboratory results. Chromosomal and blood tests are valid permanently and other tests are valid for six months. Routine blood and urine tests and routine white belt tests should be performed within the month of the treatment cycle to exclude acute inflammation of the reproductive tract. After confirming that the patient has no medical or surgical diseases or tumors that cannot tolerate ovulation promotion and pregnancy, and after confirming that the patient has the proper indications and no contraindications, the patient can enter the treatment cycle.