Introduction: Endometrial thickness is a key prognostic factor for embryo implantation in assisted reproductive technology (ART) cycles. Materials and Methods: This prospective observational study evaluated the effectiveness of intrauterine platelet-rich plasma (PRP) infusion in patients with refractory thin endometrium (RTE) unresponsive to conventional hormonal therapy. Thirteen consecutive patients were included. Autologous PRP was obtained after centrifugation, and two intrauterine infusions of 1 mL were administered 48 hours apart. Results: Mean endometrial thickness increased from 4.8 mm to 7.2 mm following PRP treatment. The clinical pregnancy rate was 84.6%. Conclusion: Intrauterine PRP infusion appears to be an effective and safe therapeutic option for improving endometrial thickness and clinical pregnancy rates in patients with refractory thin endometrium.

• Platelet-rich plasma; Thin endometrium; Refractory endometrium; Embryo transfer

Eguiluz I, De La Torre D, Marrero MA (2026) Platelet-Rich Plasma as a Treatment for Refractory Thin Endometrium. Med J Obstet Gynecol 14(1): 1199

Endometrial receptivity is a critical determinant of implantation and pregnancy success in assisted reproductive technology (ART). Several studies have established a minimum endometrial thickness (ET) of 7 mm as optimal for embryo transfer, with pregnancy rates increasing proportionally with ET [1-3]. The incidence of refractory thin endometrium (RTE) is estimated at approximately 2.5%, increasing to up to 25% in women over 41 years of age [4]. A significant proportion of ART cycles are cancelled due to inadequate ET [5-8]. Despite its clinical relevance, there is limited consensus regarding optimal treatment for RTE unresponsive to estrogen therapy [9]. This study aimed to evaluate the effectiveness of intrauterine platelet-rich plasma (PRP) infusion in improving ET and clinical pregnancy outcomes in patients with RTE.

Objective

To assess the effectiveness of intrauterine PRP infusion in patients with refractory thin endometrium unresponsive to conventional hormonal therapy and to determine the resulting clinical pregnancy rate.

This prospective observational study included 13 patients with a history of ART cycle cancellation due to RTE (ET <7 mm), treated at the Reproductive Medicine Unit of Vithas Clínica Baren (Las Palmas de Gran Canaria, Spain) between May 2021 and September 2023. Refractory thin endometrium was diagnosed by transvaginal ultrasound using a Voluson® E10 system (General Electric®) with a RIC 5–9-D endocavitary probe. Endometrial thickness was measured in the longitudinal uterine plane at the thickest point, from one echogenic endometrial border to the opposite, during days 11–13 of the cycle following estrogen preparation (Table 1). All patients received oral estradiol hemihydrate 6 mg/day (Meriestra®, Sandoz) starting on day 2 of the menstrual cycle. Once ET exceeded 7 mm, vaginal progesterone suppositories (Cyclogest®, Actavis) 400 mg twice daily were initiated.

Table 1: 13 cases of refractory thin endometrium treated with platelet-rich plasma.

Hk: Hysteroscopy. mm: Millimeters. PCOS: Polycystic ovary syndrome. UFI: Unexplained female infertility. PROM: Premature rupture of membranes. IVF: In vitro fertilization. PET: Preeclampsia.

PRP was prepared from autologous blood. Twenty milliliters of blood were collected with sodium citrate anticoagulant and centrifuged at 1200 rpm for 12 minutes (HyTissue® PRP 20, Fidia). After separation, a second centrifugation at 3300 rpm for 7 minutes was performed. The PRP fraction was activated with 0.1 mL of 10% calcium chloride, and 1 mL was infused intrauterinely using a Gynétics® IUI catheter under ultrasound guidance. The procedure was repeated after 48 hours.

Embryo transfer was performed at the blastocyst stage using a Kitazato® catheter under ultrasound guidance. Clinical pregnancy was defined as the presence of an intrauterine gestational sac with fetal cardiac activity at six weeks of amenorrhea.

During the study period, 435 ART cycles were performed, of which 13 patients (2.9%) were diagnosed with RTE. Mean patient age was 41.2 years, with 69.2% over 40 years old. Diminished ovarian reserve was the most common infertility factor (84.6%). Following two PRP infusions, mean ET increased from 4.8 mm to 7.2 mm.

All embryo transfers were performed at the blastocyst stage by the same physician. The clinical pregnancy rate was 84.6%. No adverse events or complications related to PRP treatment were observed (Table 2 and Table 3). 

Table 2: Inclusion criteria.

TVUS: Transvaginal ultrasound. 3D US: Three-dimensional ultrasound. HyFoSy: Hysterosalpingo-Foam Sonography 

Table 3: Exclusion criteria.

Adequate endometrial thickness is essential for embryo implantation. RTE, defined as ET <7 mm, remains a challenging condition in ART, often leading to cycle cancellation [10-13]. Current therapeutic strategies show variable efficacy, and no standardized treatment exists [14-18].

PRP is an autologous blood-derived product with a high concentration of platelets and growth factors that promote tissue regeneration and angiogenesis [11,19-21]. Its intrauterine application has shown promising results in improving endometrial thickness and pregnancy outcomes in RTE patients [22-26].

Our findings support previous reports demonstrating that PRP infusion can significantly improve ET and clinical pregnancy rates in patients with RTE. The observed miscarriage rate (33%) is likely influenced by advanced maternal age and associated aneuploidy risk.

Intrauterine platelet-rich plasma infusion is a safe and effective therapeutic option for patients with refractory thin endometrium, resulting in increased endometrial thickness and improved clinical pregnancy rates in ART cycles.

Ethics Approval and Consent to Participate

All procedures were conducted in accordance with 

institutional guidelines. Written informed consent was obtained from all participants.

Consent for Publication

Written informed consent was obtained from all patients for publication.

Authors’ Contributions

All authors contributed to study design, data collection, analysis, and manuscript preparation. All authors approved the final version.

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