(1) First of all, both infertile couples need to be examined at the Reproductive Medicine Clinic to confirm whether they are suitable for IVF. We will choose a treatment plan according to your situation. (2) Before the IVF treatment, you should prepare three documents: ① original ID card and copy of both partners; ② original marriage certificate and copy; ③ birth certificate issued by the family planning agency (for second child, bring the second birth certificate). (3) Before treatment, both partners need to complete the following laboratory tests: Female partner: endocrine, chlamydia, white belt routine, cervical smear, blood group and Rh (D), AIDS, syphilis, hepatitis B five, hepatitis C, liver and kidney function, blood sedimentation, blood routine, coagulation function, chest X-ray, urine routine, electrocardiogram Male partner: semen examination, external genital examination, blood group and Rh (D), AIDS, syphilis screening, hepatitis B five, hepatitis C, syphilis screening. Hepatitis B, Hepatitis C, Mycoplasma, Chlamydia, Gonococcus. (If ICSI is required, additional karyotype check for male and female) (4) Both spouses sign the informed consent form for in vitro fertilization-embryo transfer. (5) Controlled superovulation Firstly, pituitary gland down regulation: the purpose is to suppress the LH elevation and LH peak in the superovulation cycle, so that the egg development can be better and more synchronized, commonly used drugs are GnRH-a (suppression of Nadir, Dabigat). After descending regulation has been achieved, ovulation-promoting drugs are used to promote multiple follicle development. In order to evaluate the response to the follicle stimulating drugs and to decide the timing of egg retrieval, the follicle size should be monitored by vaginal ultrasound and the blood hormone level should be measured to adjust the dosage of the drugs. Ultrasound and blood hormone levels should be measured every 3-4 days at the beginning, and daily ultrasound and blood hormone levels should be measured when follicles reach a certain size. Injections of follicle-promoting drugs are given for about 10 days. When the two dominant follicles are ≥ 18 mm in diameter, HCG is injected with 10,000 international units and the eggs are retrieved 34-36 hours later. (6) Egg retrieval: Transvaginal ultrasound guided egg retrieval is a less invasive procedure and does not require too much concern. Generally, general anesthesia is not required (please inform the doctor in advance if you need general anesthesia), and you can leave the hospital after rest and observation for 0.5 to 1 hour. (7) Laboratory culture: Semen is retained on the day of egg retrieval (if retrieval is difficult, please inform the doctor in advance). The eggs are processed in the laboratory; they are fertilized in vitro; next, they are placed in the incubator for culture. Transfer usually takes place after 3 days; if there are still good embryos after the transfer, they can be frozen and preserved. If this cycle is not successful, frozen embryos can be transferred. (8) Embryo transfer: 3 to 5 days after egg retrieval the embryos are transferred to the uterus using a very thin, very soft tube; this procedure is completely painless. In general, 2 embryos are transferred, and 3 embryos are transferred in women over 35 years of age or in the second cycle of pregnancy assistance. (9) Post-transfer management: Luteal support Progesterone or HCG is administered to support the corpus luteum after egg retrieval. After the operation, you need to pay attention to urine output, measure abdominal circumference and weight, and keep in touch if there is any change. Come to the hospital on the 14th day after embryo transfer for urine pregnancy test and blood hCG to determine if you are pregnant. Generally, you should come to the center twice for ultrasound examination at 4 weeks and 6 weeks after the transfer to know the embryo status and whether there are multiple pregnancies, and to exclude ectopic pregnancy if possible. If 3 or more fetuses are found, reduction of fetus is required to ensure the safety of mother and baby. After delivery, please call or write to us to let us know the status of your delivery, the sex and weight of your baby, and whether there are any deformities.