FRESH EJACULATED SPERM IS ASSOCIATED WITH INCREASED BLASTULATION RATES COMPARED TO FROZEN EJACULATED SPERM IN FROZEN DONOR OOCYTES: A RETROSPECTIVE COHORT STUDY

OBJECTIVE: Patients utilizing third party reproduction with donor oocytes have the option to use fresh or frozen sperm. Although a paucity of data exists in the third-party population, some studies show similar reproductive outcomes between sperm sources. This study aimed to compare embryology and pregnancy outcomes between fresh and frozen sperm sources in patients utilizing vitrified donor oocytes who subsequently underwent a single, euploid, frozen embryo transfer. DESIGN: Retrospective cohort study. MATERIALS AND METHODS: Oocyte recipients from January 2017-September 2024 at an academic-affiliated center who underwent in vitro fertilization with vitrified donor oocytes and autologous fresh or frozen ejaculated sperm were included. Gestational carrier cycles were excluded. The primary outcome was blastulation rate per fertilized zygote. Secondary outcomes were rate of fertilization, euploidy, clinical pregnancy (CPR, defined as presence of a yolk sac), and live birth (LBR). Student’s t-test, fisher’s exact test, and chi-square analyses were used for comparisons. Logistic regression models controlled for male age in embryology outcomes and recipient age, BMI, and embryo grading in pregnancy outcomes. RESULTS: 4,412 frozen donor oocytes were included, with 2,420 (55%) utilizing fresh sperm and 1,992 (45%) utilizing frozen sperm. In fresh sperm cycles, the blastulation rate was significantly higher compared to frozen sperm cycles (55% vs 49%, p-value <0.01). No significant differences in CPR or LBR were observed. A subgroup analysis by sperm total motile count (TMC) showed no significant difference in blastulation nor fertilization rates in those with a low TMC (<20 million). Conversely, in those with a normal TMC (>20 million), the blastulation rate (56% fresh vs. 46% frozen, p<0.01) and euploidy rate (86% fresh vs 80% frozen, p<0.01) were significantly increased in the fresh sperm cycles compared to frozen; however, the fertilization rate was greater in the frozen sperm cycles (81% fresh vs 87% frozen, p<0.05). CONCLUSIONS: The use of fresh ejaculated sperm with vitrified frozen donor oocytes may improve outcomes compared to frozen ejaculated sperm in terms of blastulation rate and euploidy rate. Sperm TMC is an important factor to consider that can help guide patient counseling.