Abstract Study question We aimed to evaluate the effect of the platelet-rich plasma (PRP) on pregnancy outcomes in patients with RIF undergoing frozen-thawed embryo transfer (FET). Summary answer Intrauterine infusion of PRP might have more beneficial effects on pregnancy outcomes in RIF patients undergoing FET. What is known already Immunological therapies are of great interest to specialists in reproductive medicine. The immune therapies use intrauterine infusion (i.e., PRP, PBMC, G-CSF, and hCG) for endometrial immunomodulation. Despite the limited number of publications available, the results are encouraging. In the network meta-analysis, PRP, PBMC, C-GCSF, and hCG administration all significantly increased embryo implantation and clinical pregnancy compared to controls. Additionally, PRP administration resulted in a higher live birth rate than the control. This year, more research has focused on PRP as an innovative method to treat RIF. Study design, size, duration Medline, Embase, and Cochrane Controlled Register of Trials (CENTRAL) were searched from inception to July 29, 2023. The randomized controlled trials (RCTs) reporting on pregnancy outcomes of women with RIF who were administered PRP undergoing FET were included. We conducted a meta-analysis where possible using a fixed effects model. The Cochrane Handbook was used to assess the risk of bias for RCTs. Binary outcomes were pooled using risk ratio (RR) with 95% confidence intervals (CIs). Participants/materials, setting, methods Seven RCTs were included with 1,014 RIF women. The final number of women analyzed was 508 with intrauterine infusion PRP and 506 without it. Main results and the role of chance Meta-analysis showed that compared to the controls, the women who received PRP had a significantly higher embryo implantation rate (n = 2, risk ratio (RR) 2.34, 95% CI 1.65 to 3.32; P < 0.00001, I2 = 0%), biochemical pregnancy rate (n = 5, RR 1.94, 95% CI 1.60 to 2.36; P < 0.00001, I2 = 0%), clinical pregnancy rate (n = 7, RR 2.31, 95% CI 1.89 to 2.82; P < 0.00001, I2 = 0%), ongoing pregnancy rate (n = 3, RR 2.70, 95% CI 1.79 to 4.05, P = 0.0004, I2 = 31%), and multiple pregnancy rate (n = 3, RR 2.67, 95% CI 1.07 to 6.68, P = 0.04, I2 = 0%). However, PRP was not attributable to reduce the miscarriage rate (n = 3, RR 1.15, 95% CI 0.40 to 3.35; P = 0.80, I2 = 0%). Limitations, reasons for caution The proportion of small-sample studies included has to some extent affected the validity of the results. There were some variations regarding the PRP preparation process, which may result in a variable composition and concentrations of its different contents. Wider implications of the findings Intrauterine infusion PRP in patients with RIF who underwent FET may improve the pregnancy outcomes assessed in RCTs, including clinical pregnancy and ongoing pregnancy. Therefore, we suggest that PRP be included in endometrial preparation protocols. Trial registration number not applicable