What it is

PGT-A, or preimplantation genetic testing for aneuploidies, is the process of screening IVF embryos for chromosome abnormalities prior to transfer, with the goal of increasing the likelihood of achieving a successful pregnancy. PGT-A was formerly known as PGS, preimplantation genetic screening.

PGT-A has been shown to:

  • Increase implantation rates
  • Reduce miscarriage rates
  • Increase ongoing pregnancy rates
  • Increase live birth rates
  • Reduce the time to pregnancy
  • Enable confident single embryo transfer

Technology

At CooperGenomics, we are committed to offering the most advanced PGT-A technology to enable the most informed embryo selection. Our high-resolution PGT-A is performed via Next-Generation Sequencing technology and provides the best detection of:

  • Aneuploidy
  • Partial (segmental) aneuploidy
  • Unbalanced translocations
  • Some polyploidies
  • Mosaicism

Mosaicism

Mosaicism occurs when an embryo contains both euploid and aneuploid cells as a result of errors in cell division (mitosis) made during embryo growth. With the advent of high-resolution PGT-A technology, mosaicism has emerged alongside euploidy and aneuploidy as a third category of potential PGT-A results.

  Euploid1
Euploid embryo
Aneuploid1
Aneuploid embryo
Mosaic2,3
Mosaic embryo
Number of chromosomes per cell Normal Abnormal Mixed (some normal & some abnormal)
Likelihood of producing a successful pregnancy High Very unlikely Low, but possible
Recommended for transfer Yes No No; provider may consider transfer if no euploid embryos available

Unlike traditional PGT-A technologies, high-resolution PGT-A by NGS has been validated to reliably detect mosaic samples with 20-80% aneuploid cells. While more research is required to fully understand the clinical implications of embryonic mosaicism, current studies show that mosaic embryos implant less and miscarry more than euploid embryos, but some mosaic embryos maintain their viability and can lead to live birth. Given that, experts recommend considering mosaic embryos for transfer in cases where no euploid embryos are available and prioritizing mosaics based on the level of aneuploidy and chromosome impacted.

Our team is pioneering cutting-edge research and contributing to key scientific discussions and publications to drive a better understanding of the impact of mosaicism.

  1. Harton et al. (2013) Diminished effect of maternal age on implantation after preimplantation genetic diagnosis with array comparative genomic hybridization. Fertil Steril.
  2. Fragouli et al. (2015) The developmental potential of mosaic embryos. Fertil Steril.
  3. Greco et al. (2015) Healthy Babies after Intrauterine Transfer of Mosaic Aneuploid Blastocysts. N Engl J Med.

 


Reporting and Counseling

PGT-A reports are typically available within 7 days and are released to the ordering provider with results clearly presented.

PGT-A reports are typically available within 714 days of sample receipt at a CooperGenomics laboratory, though we are happy to work with your team to accommodate next day results for fresh transfers, given prior notice. Reports are released to the ordering provider, with results clearly presented on the first page(s) and euploid/normal results highlighted. We are proud to be one of the first laboratories standardly reporting mosaic results, categorized as low-level, high-level, or complex mosaic.

CooperGenomics’ expert team of specially trained, board-certified genetic counselors is available for you and your patients at every point in the PGT-A testing process.