Genetic Testing of Embryos prior to Frozen Embryo Transfer: current review of the science and personal relevance for Fertility Patients 

One of the hottest on-going debates in reproductive medicine is whether or not to perform genetic testing on embryos as part of the IVF process. This debate is fueled by the fact that not every fertility center has the equipment, the personnel and the training to perform these high tech biopsies.  This Clinical Conversation  is a review of the latest study on performing genetic testing of embryos in patients with a good prognosis for pregnancy and serves as an example of study attempting to demonstrate that there is no benefit—but their design and conclusions fall short of further analysis.

Review of New England Journal of Medicine study on Genetic Testing vs Transfer of Untested Embryos (19:46):


  • The study only included patients that were pre-screened to have the highest chance of pregnancy prior to starting the IVF process…defined as “good prognosis patients.” The average age of these patients was 29, on average they started out with at least 20 eggs and had around 7 embryos available.   
  • The study was designed as a “non-inferiority study” which means that they were trying to show that there was no difference instead of designing which treatment was associated with a better outcome.
  • The patients that were in the genetic testing arm of the study were only allowed to have three embryos undergo testing. This is not the standard way that genetic testing is actually used in clinical practice and was designed to limit the benefit of PGT-A (genetic screening for aneuploidy).
  • There was a higher risk of twins in the arm of the study that did not have genetic testing because more patients insisted on putting in more than one embryo.
  • The miscarriage rate was significantly lower in the patients that had genetic testing—something that was not highlighted by the study authors but was obvious in the data that they presented.
  • There were fewer birth defects among the patients that were in the genetic testing group.

In summary, the choice of whether or not to screen embryos prior to Frozen Embryo Transfer (FET) should be the choice of the patient and it should also be based upon the outcome data of their treatment center. One should also consider whether they are (potentially) willing to go through more than one FET to find the embryo most likely to result in a healthy pregnancy.

With informed optimism,


Robert Greene, MD, FACOG

Conceptions Reproductive Associates of Colorado

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