Should I Freeze My Embryos Before Transfer? The Two-Step Advanced Management for the PCOS Patient
From Dr. Paul Gindoff of Chelsea Fertility NYC:
There are certainly a number of useful techniques to help embryos implant. For example, transfer on day 5-6 blastocyst transfer rather than transfer on day 2-3 cellular embryo transfer. Both are time-tested, successful applications. Additionally, thawing a frozen embryo is yet another way to successfully transfer embryos.
Recent innovation suggests that implantation may improve when the uterine lining is bolstered by supplemental estrogen and progesterone – the so-called hormone replaced embryo transfer cycle. This can only be efficiently done on a non-stimulated cycle, i.e. when a patient does not take fertility drugs.
This technique is perfect for donor-recipient synchronized cycles or standard frozen-thaw embryo transfer cycles (FET). With the advent of vitrification freezing technology, the survival of the embryos is assured.
In order to “freeze-all,” as it is known, and then transfer, fertility specialists have to batch up several rounds of embryos from at least one or more egg retrievals, which means potentially one or more cycles of treatment with fertility drugs before the real attempt begins to try to get pregnant (the embryo transfer cycle). There is a delay of one to two months minimum and added costs for the extra steps in this process – the cryopreservation as well as the thaw cycle. This is called the two-step process.
Thus, the real question is: Is it worth it? Is it cost-effective or is the pregnancy rate so much higher than not doing a freeze-all scenario?
In our experience at Chelsea Fertility and from several clinical studies, it is clear that, compared to failed attempts in patients with borderline lining, this maneuver has finally led to implantation and pregnancy. So yes, there is a niche for this technique of “freeze-all.”
A large group of patients that have evidence-based studies supporting the two-step process is those with PCOS (polycystic ovarian syndrome or disease). These patients typically have a compromised endometrial lining, particularly after fertility hormone stimulation. PCOS patients have lower implantation rates due to poor egg quality and embryo quality, as well as uterine lining challenges due to baseline elevated estrogen levels and hyperstimulation from the egg retrieval cycle. They benefit from a separate cycle where endometrial lining can be optimized with hormones and a warmed (thawed) blastocyst can be transferred. Additionally, pre-implantation testing for aneuploidy (PGT-A) can enhance implantation and delivery rates by selecting the normal or euploid embryos.
In addition to the large group of patients with PCOS, the niche for the “freeze-all” technique also includes patients with known poor lining, failed implantation, or miscarriages on prior in vitro fertilization (IVF). Culturing out embryos first and then freezing them for a subsequent thaw to an endometrial lining optimized by supplemental estrogen and progesterone is a plan that addresses these pitfalls.