Since the length of the natural menstrual cycle varies from person to person and from cycle to cycle in the same patient, it is not easy to schedule egg retrieval. Moreover, only one dominant follicle develops in the natural cycle and only one embryo can be formed after fertilization, and the pregnancy rate of transferring one embryo is very low. Therefore, controlled superovulation is needed to enhance and improve ovarian function in order to obtain multiple healthy eggs regardless of the natural cycle, to provide multiple embryos for transfer, and to synchronize corpus luteum development with endometrial function as much as possible. The steps of IVF are as follows: 1. When contraindications are ruled out and indications are confirmed at the fertility center clinic, come to the registration room on the 7th floor of the clinic with the IVF registration card issued by the doctor and have the three certificates (ID card of both parties, marriage certificate and birth certificate) ready for the nurse in the registration room to check. 2.According to the lab report issued by the doctor, complete the pre-test of IVF and submit the result to the nurse in the registration room as soon as possible. 3.Couples before entering the cycle arrange time to come to the center as early as possible to listen to the pre-IVF missionary class. (Every Saturday morning from 10am-12pm). 4. Usually come to the center for a trial transfer on the 20th-21st day of menstruation and use the controlled superovulation protocol depending on the patient’s condition. 5. Controlled ovulation: Generally, GnRHa is used to bring down the FSH and LH in the body, and then HMG or FSH ovulation drugs are administered to stimulate the growth of follicles in the ovaries, and the dosage of the drugs is adjusted according to the patient’s responsiveness to the drugs, and the number of eggs obtained varies according to the patient’s age and the dosage of the drugs. 6. Follicle monitoring: In order to evaluate the effect of ovarian stimulation and to decide the time of egg retrieval, you should come to the seventh floor of the clinic on time (usually before 9:00 a.m.) according to your doctor’s instructions to monitor the size of the follicles using vaginal ultrasound and to adjust the dosage of medication in conjunction with blood hormone tests. When one or two or more follicles are larger than 1.8 cm in diameter and the number of follicles above 1.4 cm is comparable to the E2 value, human chorionic gonadotropin (hCG) can be injected to promote follicle maturation. The eggs are retrieved 34~36 hours after hCG injection. 7. Egg retrieval: Egg retrieval is usually performed under analgesic injection or intravenous anesthesia with transvaginal ultrasound guidance, and the needle is passed through the vaginal vault. 8. Sperm retrieval: The sperm retrieval will take place on the same day as the egg retrieval. Wash your hands before sperm retrieval and retain the semen by masturbation method. The small cup given is sterile, do not touch the rim of the cup or the inside of the cup when retaining. The extracted semen is processed by upstream method or Percoll density gradient centrifugation method. 9. In vitro fertilization: 4-5 hours after egg retrieval, the treated sperm and eggs are placed in the same Petri dish and co-cultured for 18 hours, then fertilization can be observed under a microscope. If the sperm quality is too poor to allow natural fertilization, fertilization must be forced by microinjection (refer to intracytoplasmic single sperm microinsemination in oocytes). 10. Embryo transfer: The fertilized egg can develop to an 8-16 cell stage embryo in 48-72 hours of in vitro culture. At this time, the number of embryos to be transferred is decided based on the patient’s age, previous pregnancy and the quality of the embryos, and the excess embryos can be frozen and preserved. No anesthesia is required for embryo transfer. Currently, embryos are mostly transferred 2-3 days after fertilization. 11.Hormone supplementation after embryo transfer: At present, progesterone is mostly given by injection to support the corpus luteum. 12.Morning urine and blood HCG test on the 14th day after embryo transfer to determine whether pregnancy. 28 days after pregnancy, ultrasound will be performed to check the number of fetus and embryo implantation site.