Effect of age and morphology on sustained implantation rate after euploid blastocyst transfer

Research question: What impact does maternal age and embryo morphology have on sustained implantation rates of euploid blastocysts? Design: This was a retrospective analysis of sustained implantation rates of euploid blastocysts stratified by maternal age and morphology. The primary analysis included 208 embryo transfers with a total of 229 embryos transferred from January 2017 through August 2020. Results: For all ages the sustained implantation rates for day 5 good quality blastocysts were higher than for day 5 fair, day 5 poor and day 6 blastocysts. At a maternal age of 36 years the best-fit sustained implantation rates were 86% for day 5 good quality blastocysts, 64% for day 5 fair, 63% for day 5 poor, and 51% for all day 6 blastocysts analysed as one group. When controlling for morphology and day of biopsy, there were higher sustained implantation rates for euploid embryos of younger patients compared with older patients. The best-fit sustained implantation rates for age 33 compared to age 39 years were 86% versus 80% for day 5 good, 71% versus 62% for day 5 fair, 59% versus 55% for day 5 poor, and 81% versus 46% for all day 6. Conclusions: There was a clinically significant higher sustained implantation rate at all ages for euploid day 5 good quality embryos compared with day 5 fair, day 5 poor and day 6 embryos.