Platelet-Rich Plasma in Recurrent Pregnancy Loss: Toward a Precision Medicine Framework for Biologically Guided Patient Selection.

Recurrent pregnancy loss (RPL), a multifactorial condition in reproductive medicine, affects approximately 1-3% of couples. Increasing evidence implicates endometrial dysfunction, immune dysregulation, impaired angiogenesis, and oxidative stress (OS) in its pathophysiology, highlighting the need for biologically targeted therapeutic strategies. In this context, platelet-rich plasma (PRP) has emerged as a regenerative approach with the potential to modulate these underlying mechanisms. This narrative review critically evaluates the biological rationale and current clinical evidence supporting PRP as an adjunctive treatment for RPL while proposing a precision medicine framework for biologically guided patient selection. A comprehensive narrative synthesis of the literature was performed, focusing on studies investigating PRP in RPL and related reproductive conditions, including thin endometrium and recurrent implantation failure (RIF). Mechanistically, PRP promotes angiogenesis through vascular endothelial growth factor (VEGF)-mediated pathways, enhances endometrial regeneration by stimulating stromal and epithelial cell proliferation, and modulates immune responses by promoting regulatory T-cell activity while attenuating pro-inflammatory signaling. In addition, PRP-derived extracellular vesicles (EVs) and microRNAs may contribute to the post-transcriptional and epigenetic regulation of implantation-related genes, including leukemia inhibitory factor (LIF) and HOXA10. Clinical studies in RIF and thin endometrium populations suggest that PRP may improve endometrial thickness, implantation, and clinical pregnancy outcomes; however, these findings constitute indirect evidence for RPL. Direct RPL-specific evidence remains very limited and is insufficient to establish a reduction in miscarriage or an improvement in live birth. These biological features instead provide a rationale for investigating PRP in defined patient subgroups characterized by impaired endometrial receptivity, defective angiogenesis, immune dysregulation, or unexplained RPL with suspected endometrial dysfunction. Accordingly, we propose that future clinical investigation of PRP should move beyond empirical use toward biomarker-informed, precision reproductive medicine strategies. Although PRP represents a biologically plausible and promising adjunctive therapy, robust randomized controlled trials incorporating standardized PRP protocols and biologically stratified patient populations are required before its routine clinical use can be recommended.