18. EUPLOID BLASTOCYSTS IMPLANT IRRESPECTIVE OF THEIR MORPHOLOGY AFTER PREIMPLANTATION GENETIC TESTING-ANEUPLOIDY USING NEXT GENERATION SEQUENCING

to a reducing time-lapse embryo score. Although there seems to be a relationship between the ploidy status and complexity of chromosome alterations with the embryo morphokinetics, time-lapse embryo score is not enough to predict chromosome alterations, and therefore, replace PGT-A. These are preliminary outcomes and further studies are being conducted to investigate the association of chromosome alterations with embryo morphokinetics and relate them with clinical outcomes. Keywords: PGT-A; time-lapse; embryo morphokinetics; aneuploidy

doi: 10.1016/j.rbmo.2019.04.069

17. DO PROGESTERONE VALUES AFFECT THE EUPLOID RATE OF EMBRYOS IN PGT-A PATIENTS?

V. García-Láez, E. Labarta, A. Mercader, A. Delgado, E. Bosch, M.J. De Los Santos IVIRMA, IVI Valencia, Spain

Introduction: In about 35% of cases undergoing ovarian stimulation may occur a rise in serum progesterone in the late follicular phase. This could produce premature luteinization and affect the endometrial receptivity. However, some studies suggest that the elevated progesterone could generate damage to the oocyte affecting the embryo quality and therefore increasing the rate of aneuploidy in the generated embryos which contributes decrease the implantation and newborn live rate. Materials and Methods: A total of 2509 patients undergoing preimplantation genetic testing for aneuploidy screening (PGT-A) were included in this retrospective study performed between 2016 and 2018. The age of patients ranged from 22 to 49 years. Laser assisted blastocyst biopsies were done in all

RBMO VOLUME 39 ISSUE s1 2019

cases by either pulling or flicking method. Antagonist protocol was used in the majority of the cases and P4 levels were measured the day of hCG administration. Poisson regression model was used as statistical analysis where progesterone was considered as a continuous variable. Other variables such age, body mass index (BMI), estradiol and ovarian sensitivity index were included in the model. P values < 0.05 were considered statistical significant. Results: The increase of ovarian sensitivity index in one unit predicted the increase of euploid embryos in 1.67 times when controlling for the rest of variables. The increase in age had a negative influence decreasing the mean number of euploid embryos by 10%. On the other hand the increase of P4 values predicted an increase in the number of euploid embryos by 7%. Conclusions: The increasing values of progesterone does not decrease the availability of euploid embryos for transfer therefore, based in this initial approach P4 seems a surrogate marker of higher ovarian response which is also positively associated with embryo euploidy. Keywords: Progesterone; euploid; embryo; PGT-A

doi: 10.1016/j.rbmo.2019.04.070

18. EUPLOID BLASTOCYSTS IMPLANT IRRESPECTIVE OF THEIR MORPHOLOGY AFTER PREIMPLANTATION GENETIC TESTING-ANEUPLOIDY USING NEXT GENERATION SEQUENCING

J. Ben Nagi1, X. Vinals Gonzalez1, R. Odia1, R. Naja2, W. Saab1, V. Seshadri1, P. Serhal1 1  Centre

for Reproductive and Genetic Health, London, United Kingdom 2  Ignomix, Surrey, United Kingdom

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Introduction: In the context of IVF, it has become imperative to emphasize on embryo evaluation in order to maximise assisted conception outcome while minimising the risk of multiple pregnancy. Despite the exponential rise in knowledge and understanding of the dynamic process of embryo development in the laboratory, the classical evaluation methods based on morphology are still considered as the gold standard methods to classify and select embryos. Morphology assessment helps embryologists to detect dysmorphic or arrested embryos but chromosomal abnormalities can still be only identified by preimplantation genetic testing for aneuploidies (PGT-A). It remains controversial the strength of morphology as a tool to ensure replacement of euploid blastocysts. The present research aims to corroborate whether blastocyst morphology, using a modified Gardner and Cornell's group scoring system, correlates with ploidy status of embryos analysed with next generation sequencing (NGS). We also wanted to ascertain whether biopsy of poor quality embryo yield a euploid embryo to transfer and thus result in a favourable outcome. This is the first data set describing the correlation between blastocyst morphology and embryo ploidy status using NGS and clinical outcomes. Materials and Methods: 296 patients underwent PGT-A. Of 1,549 blastocysts, 1,410 blastocysts had a conclusive result after PGT-A and were included for analysis. An elective single embryo transfer (eSET) policy was followed in a frozen embryo replacement cycle. A total of 179 euploid blastocysts were thawed and transferred. Clinical outcomes were categorised in four different embryo quality groups: excellent, good, average and poor. Results: Euploidy rates were 19/36 (52.7%, 95% CI 37-68), 199/470

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(42.3%, 95% 38-47), 156/676 (23.0%, 95% CI 20-26) and 39/228 (17.1%, 95% CI 13-23) in the excellent, good, average and poor quality blastocyst groups, respectively. Fitted logistic regression analysis taking into account the following co-variables; female age, embryo chromosomal status, and day of blastocyst development/biopsy showed that good (OR 0.6; 95% CI 0.4-0.8;p=0.001), average (OR 0.5; 95% CI 0.4-0.7; p=0.001) and poor (OR 0.2;95% CI 0.10.5; p=0.005) morphology with excellent morphology being the reference group was predictive of the comprehensive chromosome testing result. A logistic regression analysis was also performed on clinical outcomes taking into account for the effect of blastocyst morphology and day of blastocyst development/ biopsy. None of the parameters were shown to be significant suggesting morphology irrespective of the embryo quality category and day of blastocyst development/biopsy do not reduce the competence of euploid embryos (p>0.05).

Introduction: PGT-A was implemented to select euploid embryos and thus, to improve IVF-outcome in terms of higher live birth rate (LBR), lower miscarriage rate or shorter time-to-pregnancy. With the implementation of refined techniques such as Next Generation Sequencing (NGS) the resolution to detect (small) chromosomal aberrations in embryos increased. This holds true for as chromosomal mosaicism as well as for segmental aberrations, and consequently the amount of embryos tested as euploid decreases. This observation highlights the complex nature of genetic (in)stability during early embryogenesis and reveals the substantial shortcomings of PGT-A. The early genetic plasticity counteracts with the primary goal to improve LBR. The aim of the study was to determine when PGT-A can be recommended considering the drop-out rate starting from nonbiopsable embryos, amplification failure and drop-out due to testing as non-euploid.

Conclusions: After euploid eSET, implantation rate was 80-86%; live birth rate per embryo transfer was 60-73% and clinical miscarriage rate was found to be less than 10% and were not significanlty affected by the embryo morphology category. These results are concordant with those reported when using array compartive genomic hybridization and highlights the competence of poor quality euploid embryos.

Patients, material & methods: This retrospective single-center study (2016-2018) includes 173 hormonal stimulation cycles (71 patients). PGT-A was performed either due to three unsuccessful embryo transfers or due to three miscarriages in the patient's history. Patients with tested structural chromosomal aberrations as well as donor cycles were excluded. Blastocyst culture was performed in single step culture medium in the Embryoscope. TE-biopsy was performed on day 5-7. WGA was performed either by PicoPlex (Rubicon Genomics) or by SurPlex (BlueGenome/ Illumina). NGS was processed using VeriSeq platform with data analysis by BlueFuse Multi (Illumina).

Keywords: Preimplantation genetic testing aneuploidies; blastocyst; morphology

doi: 10.1016/j.rbmo.2019.04.071

19. PGT-A: WHEN IT IS BETTER NOT TO KNOW

S. Maximilian, W. Barbara, S. Astrid, O. Jasmin, S. Delf, Z. Martin, M. Maximilian 1  IVF

Centers Prof. Zech, Bregenz, Austria

Results: A total of 1,751 MII oocytes resulted in 752 blastocysts. TEbiopsy of at least one blastocyst was performed in 157 cycles

(68 patients). This resulted in 609 biopsied blastocysts of which 57 showed either failure of amplification or defective sequencing. 156 (25.6%) samples showed either whole chromosome aneuploidies or uniform segmental chromosomal aberrations. Further, 117 (19.2%) biopsies revealed either chromosomal or segmental mosaicism and, 140 (23.0%) were tested with a combination of uniform and mosaic aberrations. Finally, 139 (22.8%) samples were tested as chormosomally normal. This results in mean 0.8 blastocysts/cycle tested as known euploid compared to originally 4.5 blastocysts/cycle. Conclusions: High embryo losses due to non-biopsable blastocysts, amplification failure and noninterpretable results are well known but often neglected. Additionally, while NGS allows high resolution for small structural or numerical chromosomal aberrations as mosaic, the number of transferable blastocysts decreases enormous too. Chromosomal mosaicism (euploid/ aneuploid) is a major problem of PGT-A, additional problems arises from segmental chromosomal aberrations that can be present as mosaic as well. When PGT-A is recommended IVFpatients, physicians have to inform about high costs for patients, the increased number of IVF-cycles needed and the high cancellation rates. When estimating a 60% baby-take home rate after PGT-A the same number of babies would be born starting with 752 untested blastocysts considering an only 11% baby-take home rate (83.4 vs. 82.7 babies). This comparison shows that counselling for PGT-A due to RIF or RM has to be well prepared. Keywords: aneuploidy; mosaicism; segmental chromosomal abberations; drop-out rate; Next Generation Sequencing (NGS)

doi: 10.1016/j.rbmo.2019.04.072