Platelets modulate clinically relevant yet incompletely understood tissue regeneration processes, and platelet rich plasma (PRP) has been previously used with some success in various non-reproductive medical contexts. Here, we extended PRP application to ovarian tissue with a view to document impact on ovarian reserve among women attending for infertility treatment. PRP was freshly isolated from patients (n= 4) with diminished ovarian reserve as determined by at least one prior IVF cycle canceled for poor follicular recruitment response or estimated by serum AMH and/or FSH, no menses for ≥1 year. Immediately following substrate isolation and activation with calcium gluconate, approximately 5 mL of autologous PRP was injected into each ovary under direct transvaginal sonogram guidance. For each study subject, AMH, FSH, and serum estradiol data were recorded at two-week intervals post-PRP and compared to baseline (pre-PRP) values. In this pilot group, mean (±SD) patient age was 42 ± 4 years with infertility duration reported as 60 ± 25 months. Following this protocol of intraovarian PRP administration, increases in serum AMH (p = .17), decreases in FSH (p < .01), or both, were observed in all cases, sufficient to permit retrieval of 5.3 ± 1.3 MII oocytes. IVF occurred 78 ± 22 (range = 59-110) days after activated PRP injection, and results appeared independent of patient age, infertility duration, baseline platelet concentration or pretreatment antral follicle count. Each patient had at least one blastocyst suitable for cryopreservation. While autologous PRP has been successfully applied therapeutically to various tissues to accelerate healing and wound repair, this is the first description of direct injection of activated PRP into the human ovary of poor prognosis IVF patients. Evidence of improved ovarian function was noted in all who received intraovarian PRP, possibly as early as two months after treatment. Additional research is needed to clarify (and enhance) which PRP components are responsible for altered ovarian function, and to identify predictive characteristics for patients most likely to benefit from this intervention.KEYWORDS: Platelet rich plasma; fertility potential; ovary; regeneration; senescence; stem cellsGynecol Endocrinol. 2018 Sep;34(9):756-760. doi: 10.1080/09513590.2018.1445219. Epub 2018 Feb 28.