The practice of in vitro fertilization according to the published literature

James A. Grifo, M.D., Ph.D., Jason Kofinas, M.D., William B. Schoolcraft, M.D.

Volume 102, Issue 3, Pages 658-659

The “holy grail” of in vitro fertilization is identifying a single embryo that produces a healthy baby. Currently, we have the ability to select a single euploid embryo for transfer. This can be achieved without harming the embryo if the biopsy is done at the blastocyst stage. Blastocysts can be frozen with high survival rates and then transferred in a thaw cycle. The implantation of frozen thawed embryos has been shown to be superior to those transferred into an endometrium that is under the influence of the stimulated environment.

  • mperloe

    “The assumption that an embryo that is viable on day 3 but does not make a blastocyst would have made a viable pregnancy is unsubstantiated”

    While there may be no evidence to support that supposition, the lack of evidence does not invalidate the theory that an day 3 embryo might do better in the uterus than in the lab. Another assumption is that the degree of dyssynchrony between the endometrium on day 5 might be greater than day 3.

    While the existing data are clear that when sufficient embryos are available on day 3 that delaying to day 5 offers benefit. It is not clear that this is the case when a limited number of embryos are available on day 3.

    • Micah Hill

      I appreciate the above comment. My questions would be:

      1. why would an endometrium be more dyssyncrhonous on day 5 than day 3? I would think its is already advanced, it would stay dyssynchronous. If its in synchrony, it would stay that way with supplementation. Are you suggesting 2 additional days of supplementation is addative to dysynchrony?

      2. any ideas on how to design a study to address the fundamental question: that a day 3 embryo is better (or worse) off in culture to day 5 when only 1-2 embryos exist for that patient?

      The only thing I can think of is randomizing patients with 1-2 embryos to a day 3 versus a day 5 transfer. But Im not sure that actually addresses the fundamental question.

      Appreciate the authors or the posters thoughts!

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