Effect of Acupuncture on IVF Pregnancy Outcomes for Women With RIF

Inclusion Criteria: 1. Married women aged 25-40; 2. Repeated implantation failure for unknown reasons (experienced 2 or more embryo transfers of good-quality embryos without achieving clinical pregnancy); 3. Transplantable Day 3 high-quality frozen embryos or frozen blastocysts (≥3BB); 4. Estrogen and progesterone replacement therapy (HRT), endometrial thickness ≥7mm on the day of endometrial transformation. Exclusion Criteria: Patients who met any of the following conditions were not included. 1. Those who prepare for PGD; 2. Recipients of egg donors; 3. Chromosomal abnormalities in both or one of the couples (excluding chromosome polymorphism); 4. patients with implantation failure due to known embryonic factors; 5. Uterine lesions that may affect implantation (including uterine malformation, \>4cm intramural fibroids，submucosal fibroids, adenomyosis, uterine tuberculosis, intrauterine adhesions, etc. 6. Repeated spontaneous abortion (2 or more fetal loss before 28 weeks of gestation); 7. Patients with other endocrine diseases, such as thyroid disease, hyperprolactinemia, insulin resistance, diabetes, adrenal disease, etc., and poor control of hormone levels in the last 3 months; 8. Clearly diagnosed autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid syndrome, etc.; 9. Hydrosalpinx untreated; 10. BMI less than 18 or higher than 25kg/m2; 11. People with previous history of needle sickness; 12. Those who have previously participated in this study or received acupuncture treatment in the past 3 months. 13. Any situation that researchers consider inappropriate for participating in this study.