All patients prepared to thawed embryo transfer were classified into 2 groups one group will receive platelet rich plasma (PRP) infusion intrauterine and the other group will not receive platelet rich plasma (PRP) infusion

Patients candidates for Thawed embryo transfer with Repeated implantation failure were recruited from 3 centers and classified into 2 groups:

Group I: Will receive platelet rich plasma (PRP) intrauterine infusion at day 11

Group II: Not receiving platelet rich plasma (PRP)

Inclusion Criteria:

• Patients age 20-35 years
• Patients with previous implantation failure
• Patients with thin endometrium<7 mm

Exclusion Criteria:

• Patients older than 40 years
• Patients with fresh embryo transfer
• Patients with abnormal uterine cavity septate, or bicornuate uterus
• Patients with abnormal male factor or tubal factor
• Patients with abnormal embryos grade B or C.
• Patients with immunological disorders as thyroidits or systemic lupus or rheumatoid arthritis

not allowed