Clinical Pregnancy and Live Birth Outcomes From 445 Vitrified Oocyte Cycles in Australia

AIM: To describe the outcomes for women in Australia who proceed with vitrified oocyte-thaw (VOT) cycles to achieve pregnancy. METHOD: Our descriptive retrospective cohort study of 445 medical and personal VOT cycles over 12 years (2009-2021) at 11 Australian IVF clinics assessed outcomes in oocyte survival, ICSI fertilisation rate, embryo utilisation rate, clinical pregnancy rate (CPR) and live birth rate (LBR), using age-stratified data (≤ 35, 35-39 and ≥ 40 years). RESULTS: Women were on average 36.8 years of age (range 22-46 years) when undergoing planned oocyte cryopreservation (POC) cycles. Of the 445 VOT cycles, 4276 oocytes were warmed; 91% of oocytes survived and 63.5% fertilised normally. A total of 206 fresh embryo transfers and 253 frozen embryo transfers were performed. CPR per fresh transfer was 28% (58/206) and per frozen transfer was 35% (88/253), while LBR per fresh transfer was 24% (50/206) and per frozen transfer was 23% (57/253). The LBR after fresh transfer per VOT cycle initiated was 11% (50/445) and the LBR for combined fresh and frozen transfers was 23% (107/459) per VOT cycle initiated. Younger women at age of cryopreservation had higher pregnancy rates; LBR from combined fresh and frozen embryo transfers for women ≤ 35 years was 30.2% (38/126), for women 35-39 years was 24.1% (54/220) and for women ≥ 40 years was 14.2% (16/113). CONCLUSIONS: Rates of live birth from medical VOT cycles in Australia are reasonable and decrease as women age. This information can help counsel patients on VOT-cycle outcomes.