Analysis of embryonic cell-free DNA (cfDNA) present in the spent culture media (SCM) is a non-invasive alternative for preimplantation genetic testing for aneuploidies (PGT-A) that avoids the technical challenges and limitations of biopsy. Initial studies investigating this non-invasive PGT-A (niPGT-A) method reported variable concordance between cfDNA in SCM and the trophectoderm sample (\~ 30%-86%) and indicated a contribution from both the inner cell mass and trophectoderm to the cfDNA in SCM. This study aims to evaluate the use of the embryo culture medium as a source of genetic material for PGT-A and validate a niPGT-A protocol using cfDNA in SCM.
Multiple studies have demonstrated the ability to detect and amplify cfDNA from SCM, at different stages of embryonic development, with varying rates of amplification success. Differences in analytes, timing of SCM collection and the duration of embryo culture within the collected medium, performance of assisted hatching (AH), whole genome amplification methods, comprehensive chromosome screening methods and next generation sequencing (NGS) platforms, bioinformatic analyses and strategies for identifying maternal contamination all contribute to the ultimate performance of niPGT-A. This study aims to validate a noninvasive PGT-A (niPGT-A) method utilizing cfDNA released from the human blastocyst into the SCM. Patients undergoing a fertility treatment with PGT-A due to secondary infertility will be recruited. On day 6 post fertilization, SCM will be collected prior to blastocyst biopsy. The SCM is normally discarded at this stage. Trophectoderm biopsy and sample collection will follow the IVF laboratory's standard practices for clinical PGT-A. Three aneuploidy screening kits, relying on different whole genome amplification methods followed by NGS on the Ion GeneStudio™ S5 Prime System (ThermoFisher Scientific), will be compared. The concordance between cfDNA and trophectoderm biopsies will be evaluated for approximately 150 blastocysts with the best performing niPGT-A protocol. Selection of the embryo(s) for transfer will be based solely on the PGT-A result from the biopsied cells. The patient's IVF+PGT-A treatment plan and timeline will not be altered.
Study Type
OBSERVATIONAL
PGT-A and niPGT-A will be performed using next generation sequencing (NGS) analysis for chromosome copy number variation (CNV). Embryo transfers will rely solely on the results of PGT-A for trophectoderm biopsies.
General concordance between results for cfDNA in SCM and trophectoderm biopsies
General ploidy concordance rate: number of matched (euploid-euploid or aneuploid-aneuploid) result/total number cfDNA samples with a result
Time frame: 4 months
Discordance per chromosome between results for cfDNA in SCM and trophectoderm biopsies
Discordance per chromosome: number of misidentified chromosomal errors/24\*total number of embryos with cfDNA result
Time frame: 4 months
Concordance per chromosome between results for cfDNA in SCM and trophectoderm
Chromosome error concordance: number of correctly identified chromosomal errors/total number of chromosomal errors detected
Time frame: 4 months
Sensitivity of niPGT-A using cfDNA in SCM
False negative rate: 1- (true euploid result/total number of samples with a result)
Time frame: 4 months
Specificity of niPGT-A using cfDNA in SCM
False positive rate: 1- (true aneuploid result/total number of samples with a result)
Time frame: 4 months
Pregnancy outcome for patients having an embryo transfer - Implantation rate
Implantation rate = number of gestational sacs observed at echographic screening at 6 weeks of pregnancy / number of embryos transferred
Time frame: 12 months
Pregnancy outcome for patients having an embryo transfer - Biochemical pregnancy rate
Biochemical pregnancy rate = positive βhCG test of \> 15IU but no foetal heartbeat / gestational sac on ultrasound examination
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Time frame: 12 months
Pregnancy outcome for patients having an embryo transfer - Clinical pregnancy rate
Clinical pregnancy rate (%) defined by positive βhCG test and ultrasound confirmation of gestational sac or heartbeat
Time frame: 12 months
Pregnancy outcome for patients having an embryo transfer - Miscarriage rate
Miscarriage rate (%) defined by ultrasonographic visualization of one or more gestational sacs, including ectopic pregnancies, with spontaneous pregnancy loss prior to 20 weeks
Time frame: 12 months
Pregnancy outcome for patients having an embryo transfer - Clinical pregnancy rate
Ongoing pregnancy rate (beyond 20 weeks)
Time frame: 12 months
Pregnancy outcome for patients having an embryo transfer - Implantation failure rate
Implantation Failure (%)
Time frame: 12 months