Clinical management of mosaic results from preimplantation genetic testing for aneuploidy (PGT-A) of blastocysts: a committee opinion

Fertil Steril. 2020 Aug;114(2):246-254. doi: 10.1016/j.fertnstert.2020.05.014.


Since the advent of preimplantation genetic testing for aneuploidy (PGT-A) in the 1990s, substantial changes in test methodology and technology now allow the detection and reporting of intermediate chromosome copy number (commonly referred to as mosaicism) for aneuploidy in a trophectoderm biopsy sample. Clinicians are grappling with how to interpret such findings and how to counsel patients about embryo transfer decision-making. This document reviews the available literature and outlines the various issues surrounding the reporting of intermediate copy number and consideration of storage or transfer of blastocysts with intermediate copy number results. This document does not endorse, nor does it suggest that PGT-A is appropriate for all cases of in vitro fertilization.

Keywords: Preimplantation genetic testing for aneuploidy; aneuploidy; assisted reproductive technology; infertility; mosaicism.

Publication types

  • Practice Guideline
  • Review

MeSH terms

  • Aneuploidy*
  • Biopsy
  • Blastocyst / pathology*
  • Clinical Decision-Making
  • Consensus
  • Embryo Transfer
  • Female
  • Fertilization in Vitro / adverse effects*
  • Genetic Counseling / standards*
  • Genetic Testing / standards*
  • Humans
  • Male
  • Mosaicism*
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Outcome
  • Preimplantation Diagnosis / standards*
  • Reproductive Medicine / standards*
  • Risk Assessment
  • Risk Factors
  • Treatment Outcome