Bias in peer review contributing to unfounded reintroduction of PGS into IVF, warn CHR investigators in latest OPINIONs commentary

Preimplantation genetic screening, a technique that may lower IVF pregnancy chances for older women, is hastily reintroduced into IVF practice despite lack of evidence. CHR calls for a conflict-free peer review process for medical journals, in order to better examine efficacy of PGS before widespread adoption.

For immediate release

June 23, 2014 (New York, NY) – In the latest piece in OPINIONs, an online commentary series, the Center for Human Reproduction (CHR) warns against the premature reintroduction of preimplantation genetic screening (PGS) into routine infertility care. Inherent biases in peer review, CHR points out, contribute to the reintroduction.

PGS is a method of embryo selection, used in association with in vitro fertilization (IVF), that aims to remove genetically abnormal embryos before embryo transfer into the uterus, thereby, theoretically, increasing chances of IVF success. The procedure first gained popularity approximately 10 years ago, and was widely used before it was demonstrated to have the potential of actually reducing pregnancy chances, especially in older women.

CHR was then the first center to warn against the procedure’s potential to cause harm but the warnings went unheeded. Eventually, research by European investigators gained attention, and PGS fell into relative disrepute, with professional organizations formally releasing statements about its ineffectiveness.

Despite lack of any evidence that recently introduced, technologically superior PGS can improve IVF pregnancy chances, the new form of PGS is gaining popularity once again. CHR, however, cautions that claims about efficacy of this new PGS, found in even prestigious peer-reviewed medical journals, are based on inappropriate study designs and incorrect statistical data analyses. Moreover, none of these publications so far established a specific patient population in which use of PGS may, indeed, be beneficial.

Acceptance of misleading articles by peer-reviewed medical journals is, likely, the results of a typical shortcoming of the peer review process. Reviewers selected by editors are usually experts in the area of science where they are asked to review manuscripts. Experts on PGS are, however, mostly intellectually invested in the theoretically very attractive concept of PGS, or have financial ties to laboratories that perform PGS. Their conscious or unconscious biases, therefore not surprisingly, contribute to acceptance of manuscripts with serious shortcomings, and exclusion of manuscripts with opposing viewpoints. CHR calls for a more unbiased discussion of advantages and disadvantages of PGS in the medical literature.

The full-length commentary on PGS and peer review bias can be found on CHR’s website.

About Center for Human Reproduction
The Center for Human Reproduction (CHR), located in New York City, is one of the world’s leading and best known clinical and research centers in reproductive medicine and infertility. Independently vocal on issues impacting fertility patients, CHR has become known as a center of independent thinking in the profession, through its economic independence freed from political correctness and self-interests.


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Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned reproductive endocrinologist, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.