Leila Nazari - Department of Obstetrics and Gynecology, School of Medicine, Preventative Gynecology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Saghar Salehpour - Department of Obstetrics and Gynecology, School of Medicine, Preventative Gynecology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Sedighe Hoseini - Department of Obstetrics and Gynecology, School of Medicine, Preventative Gynecology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Shahrzad Zadehmodarres - Department of Obstetrics and Gynecology, School of Medicine, Preventative Gynecology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran

Background: Adequate endometrial growth is principal for implantation and pregnancy. Thin endometrium is associated with lower pregnancy rate in assisted reproductive technology. Some frozen-thawed embryo transfer cycles are cancelled due to inadequate endometrial growth.Objective: To assess the effectiveness of autologous platelet-rich plasma (PRP) intrauterine infusion for the treatment of thin endometrium.Materials and Methods: A total of 72 patients who had a history of cancelled frozenthawed embryo transfer cycle due to the thin endometrium (< 7mm) were assessed for the eligibility to enter the study between 2016 and 2017. Twelve patients were excluded for different reasons, and 60 included patients were randomly assigned to PRP or sham-catheter groups in a double-blind manner. Hormone replacement therapy was administered for endometrial preparation in all participants. PRP intrauterine infusion or shamcatheter was performed on day 11-12 due to the thin endometrium and it was repeated after 48 hr if necessary.Results: Endometrial thickness increased at 48 hr after the first intervention in both groups. All participants needed second intervention due to an inadequate endometrial expansion. After second intervention, endometrial thickness was 7.21 ± 0.18 and 5.76 ± 0.97 mm in the PRP group and sham-catheter group, respectively. There was a significant difference between the two groups. (p < 0.001). Embryo transfer was done for all patients in PRP group and just in six cases in the sham-catheter group. Chemical pregnancy was reported in twelve cases in the PRP group and two cases in the shamcatheter group.Conclusion: According to this trial, PRP was effective in endometrial expansion in patients with refractory thin endometrium.

Platelet-rich plasma, Endometrium, Embryo transfer, Randomized controlled trial