Clinical Research Directory

Inclusion Criteria: 1. Meets the criteria for RIF diagnosis (≥ 2 instances of unsuccessful transfer of high-quality embryos). 2. Age: 20 to 40 years old. 3. Planning for a cycle involving the transfer of frozen-thawed embryos (FET). 4. Possession of a transplantable D3 frozen embryo (≥6 cells) or a frozen blastocyst (≥3BC). 5. Estradiol-progesterone replacement therapy: endometrial thickness ≥ 7 mm within the period of endometrial transformation. Exclusion Criteria: 1. Individuals planning to undergo preimplantation genetic diagnosis (PGD). 2. Recipients of egg donations. 3. Chromosomal abnormalities in either spouse or one partner (excluding chromosomal polymorphisms). 4. Patients with known embryo-related factors leading to implantation failure. 5. Abnormalities of the uterus that may affect implantation (including uterine malformations, uterine tuberculosis, submucosal myomas, severe uterine adhesions, severe uterine endometriosis, myomas with a diameter of ≥4 cm, and so on). 6. Recurrent spontaneous abortions (loss of a fetus before 28 weeks of gestation occurring twice or more). 7. Individuals with other endocrine disorders, such as thyroid disorders, hyperprolactinemia, insulin resistance, diabetes, and adrenal disorders, whose hormone levels have not been well-controlled over the past 3 months. 8. Individuals with untreated hydrosalpinx; 9. Individuals with a Body Mass Index (BMI) below 18 and above 25 kg/m2. 10. Men with severe abnormalities in semen quality. Individuals with a history of needle phobia.