The Efficacy and Safety of Collagen Scaffold Loaded With Umbilical Cord Derived Mesenchymal Stem Cells in Infertile Women With Thin Endometrium or Endometrial Scarring

Inclusion Criteria: 1. Infertile patients with clear fertility desires 2. Diagnosed with thin endometrium or endometrial scarring for whom drugs and surgical interventions were ineffective 3. 20-42 years old 4. Normal ovarian function or with frozen embryos 5. Willing to actively cooperate with postoperative follow-up Exclusion Criteria: 1. With abnormal chromosome karyotype 2. With other uterine diseases including large intramural myomas, severe endometriosis, severe adenomyosis, severe congenital uterine malformations, endometrial tuberculosis, vaginitis and endometritis 3. Systemic diseases: hypertension, diabetes, and so on 4. Contraindications to pregnancy 5. Contraindications to hormone replacement therapy 6. Medical history of pelvic tumors or receiving pelvic radiotherapy 7. Involved in other clinical studies 8. Unable to adhere to the follow-up