Embryo quality and rate of development as predictive tools for embryo selection

Abstract

This study was designed to examine the relationship between embryo quality, day of biopsy, and ploidy; with the goal of improving embryo selection criteria for frozen embryo transfer (FET). In this retrospective study, data were collected from 696 patients who underwent 904 autologous preimplantation genetic testing - aneuploidy (PGT-A) cycles between 2015 and 2017. Variables included for analysis were patient age, embryo morphology and day of trophectoderm biopsy. Only good and fair embryos based on SART criteria were considered for biopsy. A total of 3,502 embryos were biopsied and analyzed. Blastocysts from autologous oocytes were assessed for morphology prior to undergoing trophectoderm biopsy on day 5 or day 6. All embryos were then vitrified and ploidy assessed by a third party testing laboratory using array comparative genomic hybridization, next-generation sequencing, or single-nucleotide polymorphism microarray. Patients who utilized monogenic preimplantation genetic testing were not included in this study. Mosaic (0.14%) and inconclusive (1.04%) results were excluded from the data set. Statistical comparisons were made by Chi-Square analysis. The average age of autologous patients was 36.7. An average of 3.9 embryos were biopsied per cycle. Good quality embryos that were biopsied on day 5 showed the highest euploid rate of 63% (857/1370). Good quality embryos biopsied on day 6 had a euploid rate of 56% (588/1048). Fair quality embryos were significantly less likely to yield euploid results, with embryos biopsied on day 5 returning a euploid rate of 48% (187/393) and embryos biopsied on day 6 returning a euploid rate of 39% (271/691). When stratified by age, this trend held significance (p<.01). Establishing a hierarchy of embryo quality and rate of development can help guide embryo selection for frozen embryo transfers for patients who did not utilize PGT. These data suggest that in the absence of PGT, embryo quality is the single most important factor in selecting a euploid embryo for transfer, while rate of development to the blastocyst stage should be considered secondarily. Further studies will be necessary to identify other laboratory and clinical factors that contribute to the success of an FET cycle.Tabled 1STATISTICAL COMPARISONS WITHIN AGE GROUPS (*p<.01)Patient AgeDay 5 GOODDay 6 GOODDay 5 FAIRDay 6 FAIRTotal Embryos Tested<3575% (322/429)*72% (248/345)*58% (70/119)*58% (115/197)*109035-3766% (287/437)*60% (180/300)*53% (59/111)*41% (75/181)*102938-4055% (190/346)*44% (129/294)*41% (48/116)*31% (65/211)*967>4037% (58/158)*28% (31/109)*21% (10/47)*16% (16/102)*416Overall63% (857/1370)*56% (588/1048)*48% (187/393)*39% (271/691)*3502 Open table in a new tab