STUDY QUESTION: Does platelet-rich plasma (PRP) intraovarian injection increase the number of retrieved oocytes in successive ovarian punctions among patients with poor ovarian reserve (POR)? SUMMARY ANSWER: The injection of PRP increases the number of retrieved oocytes without increasing the quality of developed blastocysts. WHAT IS KNOWN ALREADY: Management of women with reduced ovarian response to stimulation is one of the significant challenges in reproductive medicine. Recently, PRP treatment has been proposed as an adjunct in assisted reproduction technology, with controversial results. STUDY DESIGN, SIZE, DURATION: This placebo-controlled, double-blind, randomized trial included 60 patients with POR stratified according to the POSEIDON classification groups 3 and 4. It was conducted to explore the efficacy and safety of intraovarian PRP injection. Patients were proposed to undergo three consecutive ovarian stimulations to accumulate oocytes and were randomized to receive either PRP or placebo during their first oocyte retrieval. Randomization was performed using computer-generated randomization codes. Double blinding was ensured so that neither the participant nor the investigators knew of the treatment allotted. All patients underwent three ovarian stimulations and egg retrieval procedures. ICSI was performed after a third ovarian puncture. The primary endpoint was the number of mature oocytes retrieved after PRP or placebo injection in successive ovarian punctures. PARTICIPANTS/MATERIALS, SETTING, METHODS: Sixty women (30–42 years) fulfilling inclusion criteria were randomized in equal proportions to the treatment or control groups. MAIN RESULTS AND THE ROLE OF CHANCE: The baseline demographic and clinical characteristics [age, BMI, anti-Müllerian hormone (AMH) levels] were comparable between the groups. Regarding the primary endpoint, the cumulative number (mean ± SEM) of retrieved mature oocytes was slightly higher in the treatment group: 10.45 ± 0.41 versus 8.91 ± 0.39 in the control group, respectively (95% CI of the difference 0.42–2.66; P = 0,008). The number of mature oocytes obtained among all patients increased in successive egg retrievals: 2.61 ± 0.33 (mean ± SEM) in punction 1 (P1), 3.85 ± 0.42 in P2, and 4.73 ± 0.44 in P3. However, the increase was higher among patients receiving the assessed PRP treatment. In P2, the number of retrieved mature oocytes was 4.18 ± 0.58 versus 3.27 ± 0.61 in controls (95% CI of the difference: −0.30 to 2.12; P = 0.138) and in P3, 5.27 ± 0.73 versus 4.15 ± 0.45 (95% CI of the difference: 0.12–2.12; P = 0.029). The mean ± SEM number of developed and biopsied blastocysts was 2.43 ± 0.60 in the control group and 1.90 ± 0.32 in the treatment group, respectively (P = 0.449). The mean number of euploid blastocysts was 0.81 ± 0.24 and 0.81 ± 0.25 in the control and treatment groups, respectively (P = 1.000). The percentages of patients with euploid blastocysts were 53.33% (16 out of 30) and 43.33% (13 out of 30) for patients in the control and treatment groups, respectively (Fisher’s exact test P = 0.606). The overall pregnancy rate per ITT was 43% (26 out of 60 patients). However, the percentage of clinical pregnancies was higher in the control group (18 out of 30, 60%) than in the treatment group (8 out of 30, 27%) (P = 0.018). There was also a trend toward poorer outcomes in the treatment group when considering full-term pregnancies (P = 0.170). There were no differences between control and treatment groups regarding type of delivery, and sex of newborns. LIMITATIONS, REASONS FOR CAUTION: The mechanism of the potential beneficial effect of PRP injection on the number of retrieved oocytes is unknown. Either delivered platelet factors or a mechanical effect could be implicated. Further studies will be needed to confirm or refute the data presented in this trial and to specify the exact mechanism of action, if any, of PRP preparations. WIDER IMPLICATIONS OF THE FINDINGS: The increasing number of women with a poor response to ovarian stimulation supports the exploration of new areas of research to know the potential benefits of therapies capable of increasing the number of oocytes available for fertilization and improving the quality of developed blastocysts. An increase in the retrieved oocytes in both arms of the trial suggests that, beyond the release of growth factor from platelets, a mechanical effect can play a role. However, neither improvement in euploid blastocyst development nor pregnancy rates have been demonstrated. STUDY FUNDING/COMPETING INTEREST(S): This trial was supported by Basque Government and included in HAZITEK program, framed in the new Euskadi 2030 Science and Technology Plan (PCTI 2030). These aids are co-financed by the European Regional Development Fund (FEDER). The study funders had no role in the study design, implementation, analysis, manuscript preparation, or decision to submit this article for publication. No competing interests are declared by all the authors. TRIAL REGISTRATION NUMBER: Clinical Trial Number EudraCT 2020-000247-32. TRIAL REGISTRATION DATE: 3 November 2020. DATE OF FIRST PATIENT’S ENROLLMENT: 16 January 2021.

Menopause is a period of women’s life characterized by the cessation of menses in a definitive way. The mean age for menopause is approximately 51 years. Primary ovarian insufficiency (POI) refers to ovarian dysfunction defined as irregular menses and elevated gonadotrophin levels before or at the age of 40 years. The etiology of POI is unknown but several genes have been reported as being of significance. The fragile X mental retardation 1 gene (FMR1) is one of the most important genes associated with POI. The FMR1 gene contains a highly polymorphic CGG repeat in the 5′ untranslated region of exon 1. Four allelic forms have been defined with respect to CGG repeat length and instability during transmission. Normal (5–44 CGG) alleles are usually transmitted from parent to offspring in a stable manner. The full mutation form consists of over 200 repeats, which induces hypermethylation of the FMR1 gene promoter and the subsequent silencing of the gene, associated with Fragile X Syndrome (FXS). Finally, FMR1 intermediate (45–54 CGG) and premutation (55–200 CGG) alleles have been principally associated with two phenotypes, fragile X tremor ataxia syndrome (FXTAS) and fragile X primary ovarian insufficiency (FXPOI).