"Improved" preimplantation genetic screening (PGS) not proven to increase IVF success rates, according to systemic review


For immediate release

March 20, 2014 (New York, NY) – In a recent systematic review published by the online medical journal Reproductive Biology and Endocrinology, investigators at the Center for Human Reproduction (CHR) discuss the rising popularity of preimplantation genetic screening (PGS) and warn about uncontrolled use of the procedure in association with in vitro fertilization (IVF), which, in their opinion, still has not demonstrated efficacy in improving IVF outcomes, despite promotions to the contrary.

PGS first rose to popularity nearly a decade ago, as a method of embryo selection that was purported to improve IVF pregnancy rates and reduce miscarriage rates. Thousands of women underwent the procedure before it was determined that, rather than improving IVF success, PGS could in fact reduce pregnancy chances, especially in older women with low ovarian reserve. The procedure was declared ineffective by the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE), and the British Fertility Society and fell into relative disuse.

During the first phase of PGS’ popularity, CHR investigators were among the first to raise questions about the clinical efficacy of PGS, contributing to the eventual determination that claims of efficacy were unsupported by clinical outcome data.

Recently, however, an allegedly “improved” version of the procedure has again risen in popularity, with similar claims of enhancing IVF outcomes. “Unfortunately, our extensive review of the literature still does not support the claims,” Norbert Gleicher, MD, CHR’s Medical Director and Chief Scientist, and the senior author of the study, explains. “Patients are once again running the risk of actually harming their pregnancy chances by agreeing to use this technique in conjunction with IVF and, in addition, increase already very high IVF cycle costs.”

The systematic review points out the lack of evidence for the efficacy of PGS in improving IVF outcomes, paying particular attention to two published studies making such claims. Reanalyzing the reported data of these two studies, the authors conclude that both studies actually suggest a lack of efficacy of PGS in improving IVF outcomes, and suggest that even this allegedly improved PGS may actually reduce IVF pregnancy chances for many patients. “Given the lack of valid supporting evidence, patients should understand that this technique remains unproven,” notes Dr. Gleicher. “Unfortunately, many patients we see after they failed such treatments claim to be unaware of the experimental nature of this treatment.”

The open-access article is available at http://www.rbej.com/content/12/1/22. To read a PDF version of the article, click here.

About Center for Human Reproduction
The Center for Human Reproduction (CHR), located in New York City, is one of the world’s leading clinical and research centers in reproductive medicine and infertility. CHR has special expertise in treatment of women with diminished ovarian reserve, and pioneered many innovations, which have become mainstays of infertility treatments worldwide. Dr. Gleicher is available for further comments.


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Preimplantation genetic screening (PGS) still in search of a clinical application: a systematic review

Gleicher et al. Reproductive Biology and Endocrinology 2014, 12:22


Only a few years ago the American Society of Assisted Reproductive Medicine (ASRM), the European Society for Human Reproduction and Embryology (ESHRE) and the British Fertility Society declared preimplantation genetic screening (PGS#1) ineffective in improving in vitro fertilization (IVF) pregnancy rates and in reducing miscarriage rates. A presumably upgraded form of the procedure (PGS#2) has recently been reintroduced, and is here assessed in a systematic review. PGS#2 in comparison to PGS#1 is characterized by: (i) trophectoderm biopsy on day 5/6 embryos in place of day-3 embryo biopsy; and (ii) fluorescence in-situ hybridization (FISH) of limited chromosome numbers is replaced by techniques, allowing aneuploidy assessments of all 24 chromosome pairs. Reviewing the literature, we were unable to identify properly conducted prospective clinical trials in which IVF outcomes were assessed based on “intent to treat”. Whether PGS#2 improves IVF outcomes can, therefore, not be determined. Reassessments of data, alleged to support the efficacy of PGS#2, indeed, suggest the opposite. Like with PGS#1, the introduction of PGS#2 into unrestricted IVF practice again appears premature, and threatens to repeat the PGS#1 experience, when thousands of women experienced reductions in IVF pregnancy chances, while expecting improvements. PGS#2 is an unproven and still experimental procedure, which, until evidence suggests otherwise, should only be offered under study conditions, and with appropriate informed consents.