O-156 Fertilization rate as a novel indicator for cumulative live birth rate: multicenter retrospective cohort study of 9,394 complete IVF cycles

Study question Does fertilization rate (FR) affect cumulative success rates in assisted reproduction cycles? Summary answer These data indicate a positive association between FR with CLBR suggesting the predictive clinical relevance of this parameter and its adoption as Key Performance Indicator(KPI). What is known already Numerous studies have aimed at characterizing outcome predictors. Maternal age is historically and correctly recognized as the single most important factor impacting on the clinical outcome of ART. More recently ovarian response has also gained interest in this respect. However, the quest for novel, more comprehensive predictive factors is not over; new relevant evidence is starting to emerge. FR is a noteworthy parameter because expressing a fundamental aspect of both oocyte and sperm developmental competence. In fact it has been adopted as a key performance indicator of the IVF laboratory, to assess laboratory, operator, and gamete competence. Study design, size, duration Reported data concern a retrospective cohort study carried out between 2015 to 2017 involving 7,968 couples undergoing 9,394 complete ICSI cycles, i.e. whose all embryos were transferred or disposed.All women aged between 18-42 years were included.We excluded from analysis: surgical sperm retrieval cases, cycles resulting in neither fresh or frozen–thawed embryo transfers,cycles in which live birth were not achieved, but with remaining cryopreserved embryos,cycles of PGT, cycle with fertilization failure and standard IVF cycles. Participants/materials, setting, methods The cohort was groupped according to fertilization rate intervals based on recommendations of the Vienna Consensus (80% - Group 3). Harnessing the large size of the original dataset, further cycle stratifications were carried out based on female age (10 oocytes). Main results and the role of chance No significant difference in female age was observed between fertilization rate groups (p = 0.640). CLBR was progressively higher in relation fertilization rate in Groups 1, 2 and 3 (20.1%, 34.7%, 41.3%, P Limitations, reasons for caution The study design is retrospective and requires further refinement to control for factors that may impact clinical outcome. Wider implications of the findings These data indicate a positive association of FR with CLBR, thereby suggesting that fertilization, in addition to representing an assay for gamete quality and laboratory performance,has an independent clinical significance.Irrespective of the number of retrieved oocytes and female age, we observed that, rates of FR are positively associated with CLBR. Trial registration number None