1. Age Age is the most important factor in determining the success rate. The gradual decline of ovarian function as women age is an inevitable trend and is a process that is difficult to reverse. Most of the ovarian function declines from the age of 35, and it becomes obvious after the age of 38 and worsens after the age of 42. Declining ovarian function indicates the possibility of low egg retrieval and poor egg quality for IVF, resulting in the possibility of no embryo transfer. Therefore, it is recommended that IVF be abandoned for those older than 45 years of age, as the success rate is extremely low, less than 5%. The success rate of IVF can be 40%-60% for those younger than 35 years old, 30%-40% for those 35-38 years old, 20% for those 38-42 years old and 10% for those 42-45 years old. 2. Ovarian reserve function The function of the ovaries can be assessed by blood hormones on day 2-3 of the natural menstrual cycle and the number of sinus follicles measured by ultrasound. There are individual differences in ovarian function, therefore, the doctor needs to assess the ovarian function of the patient before formulating a protocol. Patients with high sinus follicle count, low basal FSH level, good ovarian function and no combined uterine pathology have a high success rate of IVF. 3. Uterine factors The success rate of IVF is lower in patients with combined uterine pathology, such as uterine adhesions, submucosal fibroids, longitudinal uterus, history of endometrial tuberculosis, endometritis and repeated scraping to thin endometrium. Hydrosalpinx affects embryo implantation because the retained fluid can flow into the uterine cavity. Hysteroscopy allows for accurate evaluation and treatment of uterine cavity lesions. Vaginal ultrasound to see the endometrial blood flow is an assessment of the normal uterine cavity lining and can predict the success rate of quality embryos after transfer. 4. Lifestyle and psychological factors Unhealthy lifestyle and unstable emotions are detrimental to the success of IVF, such as smoking, drinking and staying up late. Excessive stress, anxiety and depression are also another reason for failure. Therefore, you should maintain a healthy lifestyle, try to be relaxed, happy and confident before and after IVF. For patients who have difficulty managing their emotions or are psychologically disturbed, it is recommended to go to a counseling office for counseling.