The effect of platelet-rich plasma on the improvement of pregnancy results in repeated implantation failure: A randomized controlled trial

Abstract Background The success rate of infertility treatment depends on many different factors. Objective This study aimed to determine the effect of platelet-rich plasma (PRP) on the improvement of pregnancy outcomes in participants with repeated implantation failure. Materials and Methods The study is a randomized triple-blind clinical trial. The study population was 118 women with repeated implantation failure during assisted reproductive technology treatment at Tabriz Jihad-e Daneshgahi ART Center from May 2017 to December 2019. Intervention: Intrauterine injection of autologous PRP. Standard treatment of fetal transfer to the uterine cavity was performed without intrauterine PRP injection in the control group: After 4 wk, the level of β-human chorionic gonadotropin hormone in participants' blood was measured. Results Comparing the effect of intrauterine injection of PRP in 2 groups showed the level of β-human chorionic gonadotropin positive in the intervention group was 21 (43.8%), in the control group was 12 (26.1%), odds ratio = 2.20 (0.92-5.26) and p = 0.073. Conclusion The therapeutic effect in the intervention group compared to the control regarding the outcome of a successful pregnancy showed that intrauterine injection of PRP can be effective in improving pregnancy outcomes, although this improvement is not significant.


Introduction
The success rate of infertility treatment depends on many different factors, the most important of which are maternal age, causes of infertility, the weak response of the ovaries to stimulation, the influence of male factors, sperm quality, fetal quality, and various uterine pathologies. Some couples experience repeated implantation failure (RIF) after embryo transfer (ET) despite acceptable quality and without any major problems (1). According to the European Society of Human Reproduction and Embryology consortium, PIF is known as absence of a gestational sac on ultrasound at 5 wk or following 3 ET with good quality embryos or after the transfer of 10 or more embryos in multiple transfers (2).
As yet, several methods have been proposed for management of RIF. Assisted hatching, pre-implantation genetic screening, blastocyst transfer, co-culture system, hysteroscopy, sequential transfer, endometrial scratching, extra number ET, natural cycle, salpingectomy for tubal disease, oocyte donation, intra tubal ET, immune therapy, and endometrial receptivity array have been used but there has not been any proven evidence of effectiveness in these treatments (3)(4)(5).
There have been studies on the effectiveness of platelet-rich plasma (PRP) therapy, and intrauterine injection of PRP has been proposed to stimulate growth and endometrial acceptance.

Materials and Methods
The study is a randomized triple-blind clinical trial. The inclusion criteria for participants in the study were women of childbearing age with a history of RIF during ART treatments.
Exclusion criteria were women aged > 18 and aged < 45 yr old, diagnosed cancers, anemia as known hemoglobin less than 11 gr per deciliter, platelets count less than 150,000/ cc, pregnancy, use if anticoagulants, use of non-steroidal antiinflammatory drugs up to 10 days before the procedure, any physical or mental illness that affects the participant's immunity and admission and disrupt the process of implantation and participants follow-up.

Outcomes
After 4 wk, the level of β-human chorionic gonadotropin (β-HCG) hormone in participants' blood was measured and the presence of a pregnancy sac was confirmed in both intervention and control groups. The participant was followed up after 3 wk to check the fetus heart rate and monitor the pregnancy process. Then, if the pregnancy proceeded successfully until the 40 wk of pregnancy, the participants were placed under standard care, and finally live births, abortion and ectopic pregnancy were reported.

Sample size
Using the G POWER software and the following formula to determine the sample size in 2 independent groups and to study non inferiority

Statistical analysis
The analyst blindly analyzed each group with code and made comparisons between the 2 independent groups. The SPSS (ststistical pakage for social sience) software version 16 IBM Company reported the results of the project using the Kolmogorov-Smirnov, Chi-square statistical tests, Fisher's exact test, descriptive evidence, and a 95% confidence interval. P-value < 0.05 was considered significant.

Results
The process flow chart based on CONSORT statement is shown in figure 1

Registration
Evaluated for participation in the study (n = 118) Excluded from the study (n = 24) Failure to comply with the inclusion criteria (n = 13) Not accepted to participant in the study (n = 11) Randomized (n = 94)

Discussion
This study is a superiority trial type and has been conducted to evaluate the therapeutic effect of intrauterine injection of PRP in participants who suffer from RIF undergoing assisted reproduction methods. The results of this study measured the therapeutic effect in the intervention group compared to control regarding the outcome of a successful pregnancy, including live birth and pregnancy over 20 wk, which was 64%.
Comparison of the 2 groups in the hormonepositive variable showed that the odds ratio of success of pregnancy outcome in the intervention group compared to the control group was 2.20 (0.92-5.26), which was not significant.
Given that the confidence interval shows the relationship between the chance and the p-value, the comparison between the 2 groups to study the effect of intrauterine PRP injection was not statistically significant, which may be due to the small sample size.
In another study the effect of PRP on improving pregnancy rates in RIF participants have been examined, a number of women with a history of RIF was selected to transfer frozen embryos.
Intrauterine injection of 0.5 ml of PRP which contained platelets 4-5 times more than the peripheral blood samples was done 48 hr before the transfer of blastocyst, 18 women became pregnant, one premature miscarriage and one molar pregnancy. 16 pregnancies were successful and going on. In this study, PRP appeared to be effective in improving pregnancy outcomes in RIF participants (2). The study of Farimani et al. Another study compared the effects of PRP and granulocyte colony stimulating factor on infertile women with a history of RIF, which was a retrospective cohort study. The clinical pregnancy rate in the PRP group was 40.3% vs. 21.4% in the GCSF group with p = 0.025 and showed a positive effect of intrauterine PRP injection (8). In the PRP evaluation study, the transfer of frozen embryos in participants whose endometrial thickness was not accepted and had a history of RIF, a positive and significant effect on increasing endometrial thickness was also recorded, which was effective in implantation and pregnancy (9).
A recently published systematic review study examined 7 studies that highlighted the positive role of intrauterine PRP in women with a history of RIF and the transfer of frozen embryos and it has been introduced as a way to increase the possibility of successful pregnancies in assisted reproduction methods (10).

Limitation
Performing previous treatments and taking medications in previous treatments and satisfying the patient to perform the intervention are the limitations of the study.

Conclusion
Measuring the therapeutic effect in the intervention group compared to control in the outcome of a successful pregnancy showed that intrauterine injection of PRP can be effective in improving pregnancy outcomes, but this improvement is not significant.