OUTCOMES OF FROZEN DONOR OOCYTES COMPARED TO FRESH DONOR OOCYTES CYCLES, AN INTENT TO TREAT ANALYSIS

Abstract

Since the ASRM designated egg freezing as a standard method for fertility preservation and no longer experimental in 2012, the prospect of changing the paradigm of egg freezing has become a reality. However, due to the relative newness of this technology and variable success of egg freezing techniques many providers are hesitant to use this method of oocyte donation to their patients out of a concern for lower success rate compared to the traditional model of fresh direct oocyte donation. Compare outcomes of frozen donor egg thaws to the traditional fresh oocyte donation model. Retrospective cohort study in a single academic fertility center. All anonymous donor-egg recipients, undergoing IVF between 2016-2020 at a single academic center were included for analysis. An egg thaw or egg retrieval was considered a cycle for analysis. All frozen oocytes were fertilized with ICSI and insemination method for fresh donor egg cycles were determined by semen parameters and physician recommendation. PGTA was performed at the request of the recipient couple. If PGTA was performed, embryos were biopsied at the blastocysts stage and refrozen while waiting for genetic test results, then subsequently transferred in a FET cycle. Cycle outcomes such as fertilization, blast formation, total number of usable blastocysts, implantation rate per embryo transfer and total cycle potential were compared. Liver birth rate was calculated per cycle start and per transfer. Miscarriage rate was calculated per pregnancy. Fifty-seven and 42 insemination cycles using fresh direct donor oocytes and frozen donor oocytes from egg bank respectively were analyzed. The average number of MII oocytes were 14.5 and 6.0 in fresh and frozen donor oocytes groups, respectively. Fresh donor oocyte cycles resulted in higher chance to have more than one embryo available for transfer or biopsy (89.5% vs 57.1%, p < 0.001). Fresh oocyte cycles were more likely to utilize PGT-A for elective single embryo transfer (56.1% vs 11.9%, p < 0.001). In cycles using fresh donor oocytes, 47.3% (27/57) had more than one embryo transfers vs 11.4% (4/42) in frozen donor oocytes group. The live birth rates after the first embryo transfer (42.1% vs 38.1%, p = 0.688) were similar in two groups however the cumulative live birth rates per cycle to start was higher in fresh oocyte donor group (75.4% vs 42.9%, p < 0.001). A significantly lower miscarriage rate was noted with embryos derived from fresh donor oocytes (2.4% vs 18.2%, p = 0.028). Live birth rate per cycle to start is higher using fresh donor oocytes versus cryopreserved oocytes from egg bank, likely due to more surplus embryos after completion of the first embryo transfer. An increased risk for miscarriage rates was observed in frozen donor oocytes group. Large sample size studies are needed to investigate whether frozen oocyte donor from egg bank is a more cost-effectiveness strategy compared with fresh oocyte donor.