P-171 Identification of aneuploid embryos using cell free DNA in embryo culture medium
Authors: Kondo F , Kitasaka H , Watanabe H , Kida Y , Takeda S , Fukunaga N , Asada Y 
Published: June 2023

Abstract

Study question
Can noninvasive preimplantation genetic testing (PGT) using cell free DNA from embryo culture medium discriminate embryonic aneuploidy status?

Summary answer
Aneuploid embryos in older patients can be identified by cell free DNA in embryo culture medium.

What is known already
There have been reports of non-invasive PGT by analysing cell free DNA (cfDNA) released from embryos into culture medium, and found to be highly correlated with the analysis results of Trophectoderm (TE)-biopsy (Carmen.Rubio, 2020).We have initiated in 2021, a preliminary research program for the clinical application of niPGT. In aneuploid embryos, we have found a tendency for a high concordance rate between cfDNA analysis and blastocyst analysis results, suggesting the usefulness of cfDNA analysis in terms of identifying aneuploid embryos.Subsequently, we examined the usefulness of cfDNA analysis by comparing the concordance rate with cfDNA analysis and TE biopsy of blastocysts.

Study design, size, duration
After thawing pronuclear-stage frozen embryos for which consent was obtained for research use, they were co-cultured until Day 4, and then individually cultured on in new dishes.40 embryos that reached morula on day 4 or day 5 and blastocyst on day 6 or day 7 were included.

Participants/materials, setting, methods
The biopsied TE, the biopsied blastocyst, and the cfDNA obtained after individual culture were all sent to an external provider (Igenomix: Valencia, Spain) for chromosomal aneuploidy analysis by NGS. The concordance rate of the analysis for blastocysts in cfDNA and TE was calculated by dividing them into euploidy and aneuploidy, and by age. Concordance between the results of the blastocyst analysis and the culture medium were assessed according to the standards of the inspection company.

Main results and the role of chance
For the blastocyst analysis results, the concordance rate with cfDNA was 76.5% (26/34) and the concordance rate with TE was 85.3% (29/34), showing no difference. For the euploid blastocysts analyzed, the matching rate with cfDNA was 61.1% (11/18) and with TE was 77.8% (14/18), showing no difference. Similarly, for aneuploid blastocysts, the concordance rate with cfDNA was 93.8% (15/16) and with TE was 93.8% (15/16), showing no difference. Detailed analysis of aneuploid blastocysts revealed that the concordance rate with cfDNA was 88.9% (8/9) and the concordance rate with TE was 88.9% (8/9) in women under 39 years of age. In addition, the concordance rate with cfDNA was 100.0% (7/7) with TE was 100.0% (7/7) in those aged 40 and over. (Fisher's exact test)

Limitations, reasons for caution
Concordance between cfDNA and blastocyst analyzes in euploid embryos was low, continued follow-up is considered necessary.

Wider implications of the findings
In a detailed analysis of aneuploid blastocysts aged 40 years or older, Similar to TE, cfDNA showed a high concordance rate with the results of blastocyst analysis, demonstrating that cfDNA provides sufficient accuracy for identifying aneuploid embryos in women over 40 years of age.

Trial registration number
not applicable