T with certainty, is inaccurate. This, of course, raises further doubts
T with certainty, is inaccurate. This, of course, raises further doubts about the hypothesis that PGS#2 represents a diagnostic clinical improvement over PGS#1, and that PGS#1 failed for technical reasons. The study by Harton et al., therefore, at minimum demonstrates that days-5/6 biopsies offer no outcome advantage over day-3 biopsies. Since, as noted earlier, embryo culture to blastocyst stage results in definite and significant clinical as well as cost disadvantages, the study by Harton et al., indeed, strongly suggests that, if PGS is to be performed at all as a tool of IVF outcome improvement, it actually should be performed on day-3 embryos, utilizing new diagnostic platforms for determination of aneuploidy in full chromosome complements.The repositioning of PGS#2 marketingSince published studies have so far been unable to prove pregnancy outcome benefits for PGS#2, proponents of the procedure have started to promote the procedure for new indications. A prime example is the alleged PGD#2-driven ability of reducing twin pregnancies by facilitating embryo selection for elective single embryo transfer (eSET) [27].Forman et al. recently reported that this represented the primary benefit of a clinical PGS#2 trial [27]. Their Clinical Trial Registration (#NCT011408433) at [27] notes, however, that the original primary intent of the study was improvement of IVF pregnancy rates. As this failed, their original intent was replaced by the listed secondary goal of the study, the reduction of twin pregnancies via eSET. We would argue that under generally accepted study reporting guidelines, such an unreported switch in study goals is inappropriate. Specifically, the original Clinical Trial Registration lists as Primary Outcome Measures: (i) Live birth rate per randomized patient; and (ii) Comparative live birth rates of PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/28388412 patients with elective single embryo transfer (eSET) of chromosomally normal embryos (after utilizing 24chromosome copy analysis, given the acronym Comprehensive Chromosome Screening, CCS) and 2-embryo (2-ET) transfer without CCS. Only their Secondary Outcome Measures related to the risk of twinning. The published paper, however, does not refer to pregnancy rates in title of manuscript, and barely refers to pregnancy rates in the body of the manuscript. The manuscript, however, describes itself in the title as a randomized controlled trial of single blastocyst stage embryo transfer, and it really is neither. The study design per initial registration (see above) was for a non-inferiority trial, demonstrating non-inferiority of transfer of a single embryo after PGS#2 in comparison to transfer of two embryos at blastocyst stage without trophectoderm biopsy and aneuploidy determination. Moreover, at 20 non-inferiority, the trial was set to demonstrate inferiority only if any difference between these two treatment arms exceeded 20 , a clinically potentially Abamectin B1a chemical information highly significant difference. In other words, even 19.9 inferiority in clinical outcome with transfer of a single euploid embryo would, still, have fallen within the excessive non-inferiority parameters set by the authors. Pregnancy rates with single embryo transfer were, however, in absolute terms actually 4.4 lower and in relative terms 7.2 lower than with chromosomally untested double embryo transfer. Basically leaving this fact unaddressed in their manuscript, and claiming non-inferiority, the authors concentrated on above described secondary goal of their study, assess.