Transferring supposedly chromosomally “abnormal” embryos in an IVF cycle

For immediate release

October 27, 2014 (New York, NY) – When all embryos in an IVF cycles are reported to be chromosomally “abnormal” (aneuploid), under certain circumstances some of them may still be transferrable, according to a recently released OPINION from The Center for Human Reproduction (CHR), a prominent fertility center in New York City with special expertise in poor-prognosis patients. The commentary points out the still prevalent technical limitations of current preimplantation genetic diagnosis/screening (PGD/PGS) for detection of aneuploidy in embryos, which make the technique prone to some “false positive” diagnoses. CHR now argues that, though small, the additional pregnancy potential of “false positive-abnormal” embryos in poor prognosis patients with no “normal” embryos cannot be dismissed.

PGD/PGS is a technique to analyze the chromosomal health of embryos before they are implanted into the uterus. Many early-stage embryos have a mix of normal and abnormal cell lines and, therefore, are called “mosaic.” As embryos develop, normal cell lines often become dominant, while abnormal cell lines segregate away from the developing fetus into what later becomes the placenta. Many embryos in this way “self-correct.” PGD/ PGS, therefore, can lead to “false-positive” diagnoses if, coincidentally, abnormal cells (lines) are biopsied, which later may no longer be part of developing embryos.

Against this background, CHR now argues that, under carefully controlled circumstances, and with detailed informed consent, IVF centers should offer to poor prognosis patients without “normal” embryos in a given cycle, the option of transferring selected embryos deemed “abnormal” by PGD/PGS. Such transfers should only utilize embryos with so-called presumed “lethal” chromosomal abnormalities since “lethal” abnormalities either do not implant or lead to early miscarriages. “Non-lethal” abnormalities (for example Down or Turner Syndromes) often lead to births and, therefore, should not be transferred.

“‘False positive’ embryos are not a very relevant issue in patients who produce large normal embryo numbers,” says Norbert Gleicher, MD, Medical Director and Chief Scientist at CHR, “because they usually do have “normal” embryos for transfer. In women with poor prognosis, who usually produce few embryos, they, however, can make the difference between no or small pregnancy chances.”

Because of the complexities involved, comprehensive patient counseling is mandatory. Dr. Gleicher explains: “Such counseling also has to discuss that, though highly unlikely, the establishment of an ongoing chromosomally abnormal pregnancy can never be completely ruled out. Patients choosing such transfers, therefore, should commit to early prenatal genetic testing, and acknowledge the potential need for a medically induced pregnancy termination.“

CHR has recently developed a policy addressing this issue, which the center offers for consideration to other IVF centers. CHR is currently aware of pregnancies following such policies from at least three IVF centers (including CHR), leading to delivery of normal offspring.

About Center for Human Reproduction
The Center for Human Reproduction (CHR), located in New York City, is a leading clinical and research center in reproductive medicine and infertility. Independently vocal on issues impacting fertility patients, CHR has become known nationally and internationally as a center of independent thinking in the profession. Dr. Gleicher is available for additional comments.


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