Fertilization by ICSI generates a higher number of live births than IVF in a pioneer facility applying >90% single blastocyst-stage embryo transfers

Following earlier studies introducing an IVF-ICSI Split model on couples with unexplained infertility to avoid the scenario of unexplained failed or poor fertilization, PIVET has adopted a high ICSI rate approaching 90%, whereas the general rate among Australian facilities is around 60%. This observational study with retrospective data analysis reports on the IVF±ICSI procedures conducted over the period 2011 to 2019 with follow-up of ensuing pregnancies through 2020. Using autologous oocytes, 2343 women had 3434 IVF±ICSI cycles where 84.5% of women had 88.9% of initiated treatment cycles using ICSI and only 5.3% of women had 4.0% of cycles by IVF. The remaining 10.1% of women utilized the IVF-ICSI Split model for the remaining 7.2% of cycles. It was shown that oocyte fertilization rates were significantly higher for ICSI (p<0.0001), but not significant for women >40 years. The utilization rates of the ensuing embryos were ~45% across all ages with no significant differences across the ages, except for those small numbers of women ≥45 years who had a higher rate from IVF-generated embryos (p<0.0002). Pregnancy outcome were higher from ICSI-generated embryos across the age groups, being especially marked among the younger women <40 years (p<0.0001). Miscarriage rates were lowest for the IVF-generated pregnancies (overall 6.7% vs 22.8%, p<0.0001) but nevertheless the final live birth productivity rates per initiated treatment cycle remained higher from the ICSI-generated pregnancies (56.5% vs 46.3%; p<0.0001). Although this study does not meet the highest standards for EBM, it emanates from a pioneer facility with >40 years of published activity and which practices 90% blastocyst transfers in >90% SET cycles. The study supports a high ICSI rate of almost 90% and an IVF-ICSI Split rate of 10%.