#312 : Outcomes for Women Who Utilise Electively Frozen Oocytes

Abstract

Background and Aims: Frozen oocyte thaw (FOT) cycles are becoming increasingly common within IVF clinics in Australia, as women choose to freeze eggs and delay using those eggs until a more suitable time. Typically, Australian women freezing eggs are older than those women who have been studied in overseas FOT cycles. The aim of this study was to report outcomes of FOT cycles. Method: We performed a retrospective cohort study of 141 FOT cycles (from 129 patients) over a 10-year period from January 2010 to December 2020, at a single IVF clinic in Adelaide, Australia. We assessed the outcomes of those cycles in terms of oocyte warm survival, ICSI fertilisation rates, utilisation rates, pregnancy rates and live birth rates. Results: The average age of women undergoing FOT cycles was 36.5 ± 4.9 years. The reasons for egg freezing cycles included male factor (45.5%), elective (44.1%), religious (6.3%), fertility preservation (2.8%) and anonymous oocyte donation (1.4%). From the 143 FOT cycles, 1094 oocytes were collected; 82% of oocytes survived the warm process and 62% fertilized normally. There were 59 fresh embryo transfers (5.1% cleavage and 94.9% blastocyst, 22.0% DET and 78% SET) and 32 frozen blastocyst embryo transfers (12.5% DET and 87.5% SET). The pregnancy rate per fresh transfer was 30.0% (18/59) and per frozen transfer was 37.5% (12/32). The live birth rate per fresh transfer was 27% (16/59) and per frozen transfer was 37.5% (12/32). The live birth rate per initiated FOT cycle was 11% (16/143). Conclusion: Rates of live birth per initiated FOT cycle at our clinic was 11%, similar to the ANZARD live birth rate for all fresh cycles initiated in 2020 (10.9%). We therefore conclude that results for frozen oocytes are equivalent to fresh oocytes and can use this information when counselling patients on the outcomes of FOT cycles.