<p class="first" id="d1040656e93">Preimplantation genetic testing (PGT) is increasingly
used worldwide. It currently
entails the use of invasive techniques, i.e. polar body, blastomere, trophectoderm
biopsy or blastocentesis, to obtain embryonic DNA, with major technical limitations
and ethical issues. Evidence suggests that invasive PGT can lead to genetic misdiagnosis
in the case of embryo mosaicism, and, consequently, to the selection of affected embryos
for implantation or to the destruction of healthy embryos. Recently, spent culture
medium (SCM) has been proposed as an alternative source of embryonic DNA. An increasing
number of studies have reported the detection of cell-free DNA in SCM and highlighted
the diagnostic potential of non-invasive SCM-based PGT for assessing the genetic status
of preimplantation human embryos obtained by IVF. The reliability of this approach
for clinical applications, however, needs to be determined. In this systematic review,
published evidence on non-invasive SCM-based PGT is presented, and its current benefits
and limitations compared with invasive PGT. Then, ways of optimizing and standardizing
procedures for non-invasive SCM-based PGT to prevent technical biases and to improve
performance in future studies are discussed. Finally, clinical perspectives of non-invasive
PGT are presented and its future applications in reproductive medicine highlighted.
</p>