RETROSPECTIVE COHORT STUDY |
https://doi.org/10.5005/jp-journals-10016-1342 |
Platelet-rich Plasma in Managing a Thin Endometrium: An Interventional Study
1-3Department of Infertility and Assisted Reproduction, Dr Lad’s Navjeevan Hospital, Nashik, Maharashtra, India
Corresponding Author: Nitin L Lad, Department of Infertility and Assisted Reproduction, Dr Lad’s Navjeevan Hospital, Nashik, Maharashtra, India, Phone: +91 9225100642, e-mail: lads.navjeevan@gmail.com
Received on: 11 April 2023; Accepted: 01 May 2024; Published on: 28 October 2024
ABSTRACT
Aims and background: Endometrial thickness <7 mm is frequently associated with recurrent implantation failure and poor reproductive outcomes along with obstetric and perinatal complications, leading to paramount emotional and financial stress on the patients. Novel strategies are being implemented to mitigate a thin endometrium, one of which is the administration of autologous platelet-rich plasma (PRP). In this study, we have examined the efficacy of PRP in increasing the endometrial thickness.
Materials and methods: Our retrospective cohort study included 37 patients, of whom 15 received conventional hormone replacement therapy (HRT) and 22 patients received an additional intrauterine infusion of autologous PRP. Outcomes in the form of endometrial thickness and pregnancy rates were assessed. Endometrial thickness of <7 mm was used as a cutoff value for cycle cancellation.
Results: A significant increase in endometrial thickness was noted upon PRP administration (7.773 vs 6.367 mm, p = 0.001). PRP-treated group resulted in a lower cycle cancellation rate since 73% of the patients achieved a thickness of >7 mm, whereas none of the patients achieved this thickness when treated with conventional HRT. The pregnancy rates were comparable between the two groups.
Conclusion: Owing to its autologous nature, noninvasive and safe use, autologous PRP can be considered a promising adjuvant for managing a thin endometrium.
Clinical significance: A thin endometrium is a challenging situation for both patients and clinicians alike. Given the positive impact of PRP, our study will help clinicians to explore its use, especially where the conventional HRT treatments remain insufficient.
How to cite this article: Lad NL, Lad NN, Limaye RA. Platelet-rich Plasma in Managing a Thin Endometrium: An Interventional Study. Int J Infertil Fetal Med 2024;15(2):115-119.
Source of support: Nil
Conflict of interest: None
Keywords: Adjuvant therapy, Assisted reproductive technology outcome, Endometrial thickness, Platelet rich plasma, Recurrent implantation failure, Thin endometrium.
INTRODUCTION
Embryo implantation is a complex and sophisticated interplay of the endometrium and the developing embryo. Any impairment in this interplay leads to unsuccessful implantation. Some etiological reasons for implantation failure include genetic, immunological, embryonic, and endometrial factors. As for the endometrial factors, the cellular and morphological constitution of a receptive endometrium plays an essential role in successful implantation. Several studies have reported a significant association of endometrial thickness with reproductive outcomes, not only in stimulated in vitro fertilization (IVF) cycles but also in unstimulated, natural menstrual cycles.1,4 A thin endometrium is associated with a significant decline in clinical pregnancy rate, live birth rate, increased risk of spontaneous miscarriage, and ectopic pregnancy. Increased incidences of hypertensive disorders of pregnancy, small-for-gestational-age infants, and babies with lower birth weight have also been associated with a thin endometrium.5,8 Pathophysiologically, a thin endometrium is characterized by reduced vascularization, reduced epithelial growth, reduced response to oxidative stress, heightened oxygen concentration, increased collagen deposition, disrupted cellular signaling, and impaired immunological response at the time of implantation.9,12 Currently, apart from the conventional hormone replacement therapy (HRT), a few adjuvant therapies—sildenafil citrate, low-dose aspirin, granulocyte colony-stimulating factor, follicular phase-human chorionic gonadotropin (HCG) priming, pentoxifylline, tamoxifen, arginine, vitamin C, vitamin E—are being used to manage a thin endometrium; however, most of them with none to limited success.13,14 Recently, the administration of platelet-rich plasma (PRP) for a thin endometrium has gained interest among infertility clinicians after Chang et al. first explored the possible use of autologous PRP in promoting endometrial growth.15 It is observed that PRP increases endometrial receptivity, accelerates the regeneration of damaged endometrium, and decreases fibrosis.16,17 Platelet-rich plasma contains a variety of growth factors, hormonal modulators, and biomolecules that work together to promote angiogenesis and tissue regeneration. Due to these regenerative properties, the use of PRP in alleviating a thin endometrium is being explored. In this study, we retrospectively analyzed the utility of PRP in managing a thin endometrium. Outcomes in the form of endometrial thickness and clinical pregnancy rate were assessed.
MATERIALS AND METHODS
This retrospective cohort study was carried out at Dr Lad’s Navjeevan Hospital in India, within a span of 2 years (December 2020–2022). A total of 37 patients aged 25–38 years with primary infertility fulfilled the inclusion criteria. Patients with a persistently thin endometrium (<7 mm) whose previous cycles were either cancelled due to a thin endometrium or which resulted in failed IVF transfers were included in the study. Clinical history and indications of the subjects have been included in Table 1. Mean endometrial thicknesses and cycle outcomes of previous cycle have been included in Table 2. Patients with genital tuberculosis and a significant uterine abnormality were excluded from the study.
| Indications | PRP treated (n = 22) | Control (n = 15) |
|---|---|---|
| Male factor infertility | 7 | 3 |
| Premature ovarian insufficiency | 9 | 6 |
| Polycystic ovary syndrome | 2 | 0 |
| Recurrent implantation failure | 1 | 3 |
| Recurrent pregnancy loss | 3 | 1 |
| Persistently thin endometrium | 5 | 2 |
| Tubal factors | 3 | 1 |
| Unexplained | 1 | 0 |
| PRP (n = 22) | Control (n = 15) | |
|---|---|---|
| Mean endometrial thickness in previous cycle | 5.95 ± 0.60 mm | 6.06 ± 0.92 mm |
| Cycle cancellation due to endometrial thickness <7 mm | 17/22 (77.2%) | 10/15 (66.6%) |
| Pregnancy rate in cycles that proceeded to frozen embryo transfer | 1/5 (20%) | 2/5 (40%) |
| Miscarriage rate | 1/1 | 2/2 |
In total, 37 patients were identified for the study. All procedures were explained to the patient and an informed consent was obtained for the same. Out of 37 patients, 22 patients underwent PRP infusion in addition to the conventional HRT. Platelet-rich plasma infusion was introduced in our hospital from December 2021, before which, patients with a thin endometrium were treated with conventional HRT only. Of such patients, 15 individuals were identified and included in our analysis. Patients’ IVF history and endometrial thickness in previous failed cycle has been provided (Tables 1 and 2). Outcome was analyzed in terms of endometrial thickness and pregnancy rate. Endometrial thickness was measured using a transvaginal probe on an empty bladder. The thickest part of the endometrium along the longitudinal axis of the uterus was measured.
Platelet-rich Plasma Preparation
Platelet-rich plasma was prepared from autologous blood using a two-step centrifugation process. About 13.5 mL of peripheral blood was drawn and suspended in a tube containing 1.5 mL of anticoagulant [acid–citrate–dextrose solution A (ACD-A)], followed by centrifugation at 1500 rpm for 15 minutes. After centrifugation, the blood got divided into three parts, red blood cells in the bottom part, plasma in the supernatant, and a buffy coat between them. Plasma and buffy coat were taken into another tube and centrifuged at 3500 rpm for 15 minutes. This resulted in a pellet containing platelets and a clear plasma layer. About 1 mL plasma layer above the pellet was left behind and the remaining was discarded. Pellet was resuspended in the 1 mL plasma.
This PRP suspension was dipped in liquid nitrogen for 1 minute followed by thawing by rolling in palm. This freeze–thaw cycle was performed three times to disrupt the platelets and release growth factors. Ultrasound-guided infusion of 0.5 mL of PRP suspension was carried out at the fundus using an intrauterine insemination (IUI) canula. The release was sustained for 30–40 seconds.
Stimulation and Platelet-rich Plasma Administration
All patients received estradiol valerate starting at a dose of 6 mg and progressively increasing to 12 mg/day. One dose of PRP (0.5 mL) was administered on day 9 and 12 of the cycle in the test group. Luteal phase support was started once the endometrial thickness reached 7 mm. Cycle was cancelled if endometrial thickness did not reach 7 mm. Vaginal progesterone at a dose of 400 mg was administered as luteal phase support for both groups. Serum β-hCG levels were measured 2 weeks after embryo transfer to ascertain positive pregnancy.
Statistical Analysis
GraphPad Prism software (GraphPad Software Inc., California) was used to perform statistical analysis. Normally distributed parameters were analyzed using Student’s t-test. A p-value of 0.05 or less was considered statistically significant. Unless otherwise specified, values were expressed as the mean ± standard deviation (SD).
RESULTS
Endometrial Thickness “Before and After” Platelet-rich Plasma Infusion
In total, 22 patients underwent PRP infusion. All patients tolerated the procedure well and showed no side effects. “Before and after” measurements were taken on day 9 and on the day of frozen embryo transfer, respectively. There was a significant increase (p-value < 0.0001) in the endometrial growth after PRP infusion. The mean endometrial thickness before instilling PRP was 6.205 ± 0.782 mm and that after infusion was 7.773 ± 1.279 mm.
Endometrial Thickness between Platelet-rich Plasma and Hormone Replacement Therapy
Endometrial thickness of patients in both groups was noted on the day of embryo transfer. Platelet-rich plasma showed a significant increase (p-value = 0.001) in endometrial thickness compared to the conventional HRT. The mean endometrial thickness in PRP treated group was 7.773 ± 1.279 mm and that in HRT group was 6.367 ± 0.973 mm (Fig. 1). In the PRP-treated group, 16/22 (73%) patients showed an endometrial thickness above 7 mm, whereas none of the patients could achieve this thickness in the HRT-treated group. About 6/22 (27%) patients in the PRP group, whereas 13/15 (86%) in HRT group showed an endometrial thickness ranging between 6 and 7 mm. None of the patients showed an endometrial thickness below 6 mm in PRP, whereas 2/15 (14%) patients in HRT group showed an endometrial thickness below 6 mm (Fig. 2). Due to insufficient endometrial thickness, embryo transfer cycle was cancelled in patients with endometrial thickness below 7 mm.
Fig. 1: Graphical comparison of the mean endometrial thickness between PRP and HRT treated groups; *** denotes p-value < 0.001
Fig. 2: Distribution of endometrial thickness in PRP vs HRT; *** denotes p-value < 0.001; NS denotes nonsignificant difference
Pregnancy Rates
About 11/22 (50%) patients in the PRP-treated group, whereas 6/15 (40%) patients in the HRT-treated group achieved a positive pregnancy. Pregnancy rate in PRP-treated group was higher, although nonsignificant.
DISCUSSION
Platelet rich plasma essentially consists of the plasma and the platelets. Platelets are produced in the bone marrow and are well known for their ability to clot blood. They also have a high concentration of endocrine and paracrine signaling molecules. During implantation too, there is a heightened activity of these signaling molecules, which enable successful implantation and pregnancy preservation. Therefore, in the recent years, scientists began exploring the possible use of PRP in mitigating a thin, nonreceptive endometrium. Most of the regenerative effects of PRP can be attributed to the fact that platelets host a variety of growth factors such as transforming growth factor (TGF-β1, TGF- β2), platelet-derived growth factors (PDGF-AA, PDGF-BB, PDGF-AB), hepatocyte growth factor (HGF), insulin-like growth factor 1 (IGF-1), fibroblast growth factor (FGF), epidermal growth factor (EGF), and vascular endothelial growth factors (VEGF).16,19 The dense granules of the platelets also contain calcium ions, serotonin, histamine, and dopamine that are essential in tissue homoeostasis.20,21 PRP administration also upregulates several genes that are essential for implantation, pregnancy preservation, and parturition. Some of those genes which are upregulated after PRP administration are cyclooxygenase-2 (COX-2), tumor protein-53 (TP-53), estrogen receptors-alpha (ER-α), estrogen receptors-beta (ER-β), and progesterone receptors (PR) (Fig. 3).2,20-22 These regenerative properties are speculated to be beneficial in improving endometrial thickness, thereby increasing the chances of implantation.
Fig. 3: Graphical representation of the pathophysiological changes achieved after PRP administration in a thin endometrium; COX-2, cyclooxygenase-2; EGF, epidermal growth factor; ER, estrogen receptors; FGF, fibroblast growth factor; HGF, hepatocyte growth factor; IGF, insulin-like growth factor; PDGF, platelet-derived growth factor; PR, progesterone receptors; TGF, transforming growth factor; TP-53, tumor protein-53; VEGF, vascular endothelial growth factor
In this study, we analyzed whether the administration of autologous PRP could increase the endometrial thickness. Our before–after analysis showed a substantial increase in endometrial thickness upon administration of intrauterine PRP. When compared to conventional hormonal therapy, administration of additional PRP infusion yielded significantly better results at increasing the endometrial thickness. A thickness of <7 mm is associated with lower clinical pregnancy rate, lower live birth rate, and increased risk of miscarriage and ectopic pregnancy. Therefore, many clinicians choose to cancel the cycle at a thickness <7 mm. Interestingly, none of the patients undergoing HRT could achieve an endometrial thickness of >7 mm, whereas when treated with PRP, a significantly higher proportion (73%) of patients achieved a thickness >7 mm. The use of PRP as an adjuvant results in less cycle cancelations, thereby preventing physical and emotional stress on the patients. The pregnancy rates between the two groups however were comparable. One of the reasons could be the heterogeneity of clinical indications. Some of the couples included in our study had clinically significant male factor infertility, thereby considerably affecting the quality of embryos transferred and, in turn, the pregnancy outcomes. The limitations of our study are its small sample size, heterogeneity of clinical indications, and retrospective nature. An ideal study design would be a large randomized control trial with outcomes compared in the form of endometrial thickness, pregnancy, miscarriage, and live birth rates.
Since PRP is autologously sourced, it is technically safe with minimal risk of disease spread and immune/allergic responses.20,21 Currently, the administration of PRP for endometrial indications is performed in two different ways, one is intrauterine infusion using an IUI canula or, secondly, through hysteroscopic instillation. Alkatout et al. have reported an endometrial thickness of >7 mm in 75% of the patients following hysteroscopic PRP instillation,23 and we have reported an endometrial thickness of >7 mm in 73% of the patients, using intrauterine infusion. Thus, irrespective of the mode of PRP administration, there is significant increase in the endometrial thickness following PRP therapy. In fact, our procedure of intrauterine infusion is noninvasive, anesthesia-free, and easy-to-perform compared to hysteroscopic instillation, thereby waging a better patient compliance for the procedure.
CONCLUSION
Our study indicates that PRP can be a promising tool for increasing endometrial thickness, especially in patients where the conventional HRT is insufficient.
Clinical Significance
Several studies have documented the detrimental effect of thin endometrium on reproductive outcomes. Owing to its dynamic nature and sheer complexity, overcoming a thin endometrium remains a challenge for clinicians. Our study showed the positive impact of PRP in the management of thin endometrium. A significant increase in endometrial thickness and reduced cycle cancellation rate were promising outcomes in our study. Our research broadens the possibilities for the use of PRP in thin endometrium, especially when conventional management options remain inadequate.
ORCID
Nitin L Lad https://orcid.org/0000-0001-9271-2483
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