Comparison of Cumulative Live Birth Rates Between Fresh and Vitrified Donor Oocytes.

Background Oocyte donation is a well-established treatment for age-related infertility, diminished ovarian reserve, and other reproductive challenges. The introduction of vitrification has expanded its feasibility by enabling oocyte cryobanking, reducing logistical constraints, and improving accessibility. However, debate persists regarding whether clinical outcomes differ between fresh and vitrified donor oocytes, particularly when embryos undergo double vitrification at both the oocyte and blastocyst stages. This study aims to compare cumulative live birth rates between fresh and cryopreserved donor oocytes in oocyte donation cycles. Methodology This retrospective cohort study analyzed 214 oocyte recipient cycles conducted at Assisting Nature Fertility Center from January 2018 to January 2023. Group A (n=112) received fresh donor oocytes, while Group B (n=102) received vitrified donor oocytes. Key outcomes included fertilization rate, blastulation rate, cumulative positive β-human chorionic gonadotropin rate, cumulative clinical pregnancy rate, and cumulative live birth rate. Statistical comparisons were performed using t-tests and chi-square tests, with significance set at p<0.05. Results Oocyte survival after thawing was 96%, with similar fertilization (87% vs. 84%) and blastulation rates (70% vs. 65%) between fresh and vitrified oocytes, respectively. Live birth rates after the first embryo transfer were comparable between Group A (59.8%) and Group B (58.8%; p>0.05). Cumulative live birth rates, including pregnancies from second and third embryo transfers, were 69.6% in Group A and 66.7% in Group B, with no statistically significant difference (p>0.05). Despite a slight trend toward lower initial pregnancy rates in the vitrified donor oocyte group, cumulative outcomes remained comparable between the two groups. Conclusions Both fresh and cryopreserved oocyte donation programs produce similar fertilization, blastulation, and cumulative live birth rates. The findings suggest that double vitrification (oocyte and embryo stages) does not negatively impact embryo viability or pregnancy success. Oocyte vitrification should be considered a routine option in oocyte donation programs if laboratories ensure their vitrification protocols yield outcomes comparable to fresh oocyte cycles.