Multicentre trial of preimplantation genetic screening reported in the New England Journal of Medicine:: an in-depth look at the findings

A randomized clinical trial of 406 patients with advanced maternal age by Mastenbroek and co-workers recently published in the New England Journal of Medicine showed a significant decrease in pregnancy outcome after preimplantation genetic screening (PGS). It is our opinion that this study suffers from a number of insurmountable inaccuracies and that these are either a direct consequence of the inexperience of the team or of a general disregard of vital guidelines reported in the literature. Most importantly, the authors show that in their hands embryo biopsy may affect as many as half the embryos. The error rate was not presented, shedding doubt on the authors' abilities to reliably diagnose the biopsied cells. An evaluation of the study indicates that poor biopsy technique, sub standard fixation and FISH methods, poor IVF outcomes and inappropriate patient selection are the cause of the discouraging results obtained by these authors rather than problems inherent to PGS.