Blastocyst transfer in day-5 embryo transfer depends primarily on the number of oocytes retrieved and not on age

Pregnancy outcome of day 3 versus day 5 embryo transfer: A retrospective analysis

“…This meta-analysis supported this finding, when an equal number and up to two embryo transfer policy is followed with risk of higher probability of embryo transfer cancellation and less number of embryos cryopreserved in the blastocyst group [9]. This is considered a major drawback with possibility of failure to develop blastocysts stage embryo and thus failed to transfer embryos [15,16].…”

Age-associated changes in bovine oocytes and granulosa cell complexes collected from early antral follicles

“…A decrease in the ability of oocytes to fertilize and develop to the blastocyst stage has been observed with increasing age in cows as well as human with reproductive capacity [4][5][6][7][8][9][10][11]. In addition to the low quality of oocytes, ovarian reserve also declines with age in humans [12] and the reduced antral follicle counts reflect the sub fertility in reproductive aging women as well as cows [13,14].…”

Blastocyst development rate impacts outcome in cryopreserved blastocyst transfer cycles

“…Presently, more than 50% of all zygotes produced develop into blastocysts (1,2). Extended culture time allows for the assessment of embryo physiology by examining morphology beyond genomic activation, a reflection of embryonic potential as opposed to innate oocyte processes (3).…”