Preimplantation genetic screening is alive and very well: Really?

12 09 2013

To the Editor:

The September issue featured Views and Reviews on preimplantation genetic screening (PGS), including an editorial by Meldrum (1), declaring PGS “alive and very well,” four reviews of technical aspects of the procedure, and three articles by the Scott group. Unfortunately, lacking was a critical and balanced presentation of the subject.

The concept of PGS is not new. It was proven useless in a prior incarnation, though unfortunately only after thousands of women reduced pregnancy chances by utilizing the procedure (2). Now history appears to repeat itself, with many investigators promoting an improved version involving day 5/6-blastocyst trophectoderm biopsy in place of day-3 embryo biopsy and 24-chromosome copy number analysis by various available technologies in place of fluorescence in-situ hybridization (FISH).

All above noted articles uncritically accept that the earlier PGS failure was due to technical shortcomings of day-3 biopsies and chromosomal analyses by FISH. They assume that these shortcomings are remedied by the utilization of trophectoderm biopsy and new 24-chromosome copy analyses, and that PGS now fulfills its presumed destiny of improving in vitro fertilization (IVF) outcomes.

But what if PGS did not fail because of technical shortcomings? What if it failed because PGS should not be applied indiscriminately to every patient or because embryo selection by PGS statistically simply does not work in older women or with low ovarian reserve? Wouldn’t we then only repeat the same mistakes all over? Read the rest of this entry »