Does personalized embryo transfer based on era improve the outcomes in patients with thin endometrium and Rif in Self Versus Donor Programme?

Author(s): Priya Selvaraj*, Kamala Selvaraj, Mahalakshmi Sivakumar, Hamini Chandrasekar and Valarmathi Srinivasan Aim: This study was designed to explore the influence of personalized Embryo Transfer (pET) with the guidance of endometrial receptivity array (ERA) on reproductive outcomes in patients with Recurrent Implantation Failure (RIF) and thin endometrium, and to determine its efficacy in self versus donor gamete programme. Settings and designs: A retrospective study condu ... Abstract View Full Article View DOI: 10.17352/jgro.000092

researches substantiate the fact that patients with impaired uterine environment exhibit a displaced WOI [5]. It has also been reported that WOI occurs 1-2 days earlier in women undergoing ovarian stimulation than in natural cycle [2].
In order to ascertain an appropriate marker for endometrial receptivity with higher accuracy, a molecular diagnostic tool called 'Endometrial Receptivity Array' (ERA) was developed.
It appraises the expression of 238 genes which infl uence the development of endometrium during the WOI. The sensitivity and specifi city was noted to be 99.75% and 88.57%, respectively. The results were reproducible in the same patients after 2-3 years from the date of the fi rst test [6][7][8]. ERA test determines the duration of progesterone exposure required by the endometrium to produce a receptive niche which gives rise to personalized embryo transfer (pET) [5]. Among various factors which hinder successful reproductive outcomes, thin endometrium has a negative infl uence on the implantation process, in most cases leading to recurrent implantation failure (RIF). Hence, ERA can be performed to confi rm the receptivity of a thin endometrium before preparing for frozen embryo transfer (FET). It guides the process of pET if a displaced WOI is encountered in patients with RIF [9,10]. This retrospective study was designed to explore the infl uence of pET with the guidance of ERA on reproductive outcomes in patients with RIF and thin endometrium, and to determine its effi cacy in self versus donor gamete programme.

Study design
This retrospective study was conducted from January 2014 until December 2019 at GG Hospital, Fertility research and women's speciality Centre, Chennai, India. The study population comprised of 722 women who had documented poor/thin endometrial lining and previous IVF failures. A poor endometrial lining was defi ned as an endometrial thickness measuring ≤0.7 cm on a trans-vaginal ultrasound during the peri-implantation period. The 722 women who were inducted in this study were divided into four groups. Group A (n=179) comprised of patients using self-gametes and Group C (n=180) consisting of patients using donor gametes, the patients under these groups underwent the ERA test as described below.
Both the groups were compared to their respective controls, Group B (n=181) and Group D (n=182) in which ERA test was not performed. All the patients were given oral and written information regarding the procedure and consents were taken for the same. The baseline characteristics of the study population have been elucidated in Table 1.
The stimulation protocols employed for patients using selfgametes comprised of the long and short protocol based on factors such as age, previous reproductive outcomes, hormone values, quality and quantity of oocytes and embryos. The known poor responders with poor quality embryos, and also the patients who were assigned for PGT-A were excluded from the study.

Stimulation protocol
The hyper stimulation regimes in long and short protocols were similar consisting of day 2/3 scan followed by hormone In the long protocol, the trigger was recombinant HCG of 250 IU (Merck, Germany) and in the short protocol, GnRH agonist inj. Decapeptyl 0.1 mg (Ferring, Germany)was given. For dual trigger HCG 250 IU was given along GnRH agonist.

Era cycle
The ERA test was performed in a hormone replacement cycle. The women were given incremental doses of EstradiolValerate (2mg) (Zyduscadila, Sikkim) from day 2/3 of their menstruation phase until the mid-cycle assessment on day 12/13. Generally, the minimum dose is 6/8 mg andincreased up to a maximum dose of 12 mg. On day 16, a trigger of HCG 10,000 IU (Amlife, Gujarat) was administered along with starting dose of vaginal micronized progesterone 400mg. There on, micronized progesterone was given in both oral and vaginal suppository form from a minimum dose of 800 mg to a maximum dose of 1200 mg (Sun Pharmaceuticals, Gujarat). The procedure was performed on day 21 (P+5) of the cyclewhich involves a biopsy taken trans-vaginally using an endometrial sampler or Probet. The tissue was transferred to a cryotube containing 1.5 ml of RNA stabilizing agent (Igenomix, Delhi) and vigorously shaken for few seconds until thoroughly mixed. The sample was stored at 4°c until shipment at room temperature to Igenomix, Spain for the transcriptomic analysis. The results are usually classifi ed as Receptive, Pre-receptive or Post receptive. The latter two recommendations by the lab are provided with the estimated time for pET. Sequential transfers were performed consisting of cleavage stage embryos on P+3 and blastocyst on P+5, whereas in single transfers, either cleavage stage embryos (P+3) or blastocyst (P+5) were transferred according to the personalized ERA profi le. The primary outcomes were then measured as Pregnancy rate (PR), Clinical pregnancy rate (CPR), Implantation rate (IR), Miscarriage rate (MR) and Live Birth rate (LBR). Statistical analysis was performed using t-test in SPSS software (12.0).

Results
A total of 722 patients with thin endometrium and RIF were recruited in this study. ERA test was performed for 359 patients and the results were documented ( Table 2, Graph 1). In Group A (self), 45.25% of the patients exhibited receptive endometrium with early receptive (12.85%) and late receptive (2.79%). Non receptive endometrium was classifi ed into pre-receptive (29.05%) and post-receptive (10.06%). On the other hand, patients under Group C (donor) returned with a receptive profi le of 50.56% with 11.67% early receptive and 3.89% late receptive. 18.88% of the patients showed pre-receptive condition while post receptive was observed in 15.00% of the patients. The era profi le of the study groups have been elucidated in table 2 and graphically represented in graph 1 Table 2.

Self (Group A And Group B)
In Group A and Group B (Control), PR was observed to be 55.31% and 51.90%, respectively. No statistical difference was recorded (P=0.521). The difference in the IR was statistically insignifi cant (P=0.81) between Group A (24.77%) and Group B (24.07%).CPR was higher in Group A (48.60%) than in Group B (43.09%). However, there were no signifi cant differences observed (P=0.29). LBR in Group A was 85.06% and 75.64% in Group B. This yielded a statistically insignifi cant result with p-value 0.13. MR in Group A and Group B was 14.94% and 24.36%, respectively (P=0.192). The data have been elucidated in Table 3 and graphically represented Graph 2.

Donor (Group C and Group D)
PR in patients who underwent ERA in Group C (68.33%) and in control Group D (52.19%) exhibited statistically signifi cant difference (P=0.0017). IR was found to be statistically signifi cant (P=0.0023) between Group C (30.31%) and Group D (21.51%). CPR was superior in patients under Group C with the rate of 59.44% as compared to Group D which showed 43.41%. This yielded a statistically signifi cant range (P=0.002).There were signifi cant differences documented in LBR and MR (P=0.05, P=0.028). LBR in Group C was 79.44% whereas in Group D it was 67.09%. MR in Group C and Group D was 20.56% and 32.91%, respectively. The data have been elucidated in Table 4 and graphically represented Graph 3.

Discussion
In a study conducted by Diaz-Gimeno, et al. to test the accuracy and reliability of the ERA test versus histological dating, they analysed 49 samples to compare the endometrial dating accuracy out of which 13 samples predicted through ERA identifi ed the phase of the cycle more accurately than through the histological dating done by the pathologists. 16 samples were properly dated by using both the methods. They concluded that ERA exhibits a higher accuracy for endometrial dating throughout the luteal phase and endometrial receptivity than the anatomical approach that has been used since 1950s [11]. Ruiz -Alonsa, et al. submitted a report on the positive impact of pET on a patient with RIF. The underlying problem was likely found to be of endometrial origin. Hence, an endometrial biopsy was collected on day P+5 in an HRT cycle and received a pre receptive result. A two day displacement of WOI was diagnosed and personalized adjustments were done. pET was performed at P+7 with two blastocyst which resulted in twin pregnancy. This was followed by a pilot study through which they inferred that the personalization of the embryo transfer timing based on the ERA report can make a positive difference in reproductive outcomes in patients with RIF [12].

Conclusion
In conclusion, ERA is believed to be a promising molecular tool in the diagnostic platform and could establish a personalized window of implantation in patients with thin endometrium and RIF.The present study shows that ERA test has superior benefi ts in patients who have previously failed despite using donor gametes. Its relevance is expected to increase with emerging data which would apparently strengthen the pregnancy outcomes in the donor gamete recipients. However, a prospective study with a large sample size is required to highlight its importance more certainly.