While the results of PGT-M are highly accurate (>97%), PGT-M is still considered a screening test, meaning it is not diagnostic. It does not diagnose the transferred embryo as having or not having the pathogenic variant(s) that predisposes someone to a genetic disorder. Transferring embryos introduces an element of human error, as well as laboratory error. For these reasons, patients are counseled on the option of minimally invasive diagnostic prenatal tests including chorionic villus sampling (CVS) or amniocentesis to confirm that the fetus does not have the pathogenic variant(s). Current technology does not have any non-invasive options specific enough to test for single-gene disorders.
Non-invasive prenatal screening (NIPS), which uses a blood sample taken around 10 weeks of pregnancy, is now commonly available as a first-line screen during pregnancy for everyone. It tests for a limited number of whole-chromosome abnormalities during pregnancy. NIPS should confirm the PGT-A findings, but this test will not assess the accuracy of PGT-M. A healthcare provider can review these options with you in more detail as there are risks and limitations for each test that should be considered carefully.