#121 : The Easier Blastocyst Biopsy, The More Trophectoderm Cells We Got

Abstract

Background and Aims: Several studies showed various factors associated with pregnancy outcomes after the euploid embryo transfer, including parental, endometrial, and embryo biopsy. The consensus of the most suitable biopsied cell number is 5-10 cells among IVF labs. Therefore, for embryologists, how to have a steadily manipulated blastocyst to get an appropriate biopsied trophectoderm cell number is crucial. However, the factors related to biopsy manipulation are still being determined. Here, we retrospectively analyze the DNA concentrations from biopsied cells to test the hypothesis TE grading, hatching status, and biopsy day correlated with embryologists’ biopsy handling. Method: A retrospective study enrolled 212 blastocysts from 49 PGT-A cycles (NGS platform) from September 2021 and March 2023 at the Fertility and Reproductive Genetic Center of Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan. All the TE cells were removed by mechanical cutting by embryologists following the lab standard operating procedure. This study excluded five blastocysts (2.4%, 5/212) for the unsuccessful whole genome amplification (WGA), i.e., DNA concentration was less than 10 ng/[Formula: see text] l. Results: No difference in average DNA concentration was found between embryo ploidy status (Fig. A, P=0.8), embryologist (Fig. A, P=0.65), and TE grading (Gardner TE grading B vs. C, P=0.8). However, combined hatching status and day of the biopsy revealed a significantly higher DNA concentration in the hatching Day 5 to Day 7 groups than in the hatched Day 5 to Day 7 group (Fig. B, P[Formula: see text]0.0001). Conclusion: Our data suggest that the embryo ploidy status and Gardner grading of TE cells did not affect embryologists’ steadily performing biopsies. Interestingly, the easier biopsy, the more TE cells we got. This result implies that the hatching (Gardner expansion grade 5) embryo has a higher potential for damage after trophectoderm biopsy.