Should we freeze all embryos and transfer them later?
Over the last few years some colleagues have started to propagate the so-called all-freeze protocol for most, if not all, IVF cycles. What they mean by that is embryos should practically never be transferred in a fresh cycle because, based on their hypothesis, the endometrium in stimulated cycles is much less favorable to implantation than in natural cycles.
We have addressed this hypothesis before in the VOICE, concluding that the studies on which this hypothesis was based on where statistically highly inappropriately manipulated. Certainly in poorer prognosis patients, including older women, we feel that all-freeze cycles can to significant degrees negatively affect IVF outcomes because eggs from older women (and embryos made from these eggs) do not freeze and thaw as well as those from younger women. CHR, therefore, views unnecessary embryo freezing as “giving pregnancy chances away for no good reason.”
Poorer prognosis patients, of course, can afford this much less than better prognosis patients, who often produce excess embryos and where loss of some embryos really does not as much matter.
CHR considers all-freeze cycles yet another “fashion-of-the-moment,” which more harms than benefits. It is also an additional example for what, unfortunately, is just too common practice in our specialty, which is investigating treatments in highly selected (and usual good-prognosis patients) and then applying the results of those studies to all patients. In most IVF centers good prognosis patients represent only approximately 20% of all patients. In other words, in the other 80%, such “fashions-of-the-moment” either offer no benefits or even cause harm to IVF outcomes, as in this case.
There is also another reason why all-freeze cycles have become popular in some IVF centers and that reason is that all-freeze cycles allow for relatively easy manipulation of a center’s IVF cycle outcome reports. As CHR investigators not too long ago demonstrated, some of the most prominent IVF centers in the nation are among the most profound abusers of the embryo-banking (another term for all-freeze cycles) loophole [Kushnir et al;, Reprod Biomed Online 2017;35(2):161-164]. When their real outcomes were analyzed excluding embryo banking cycles, those centers actually demonstrated lower live birth rates than the median rates of all other IVF centers.
This is a part of the November 2018 CHR VOICE.
Norbert Gleicher, MD, FACOG, FACS
Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, 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.
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