The age-related required number of zygotes estimated from prior clinical studies of preimplantation genetic testing for aneuploidy (PGT-A)

Women who are undergoing preimplantation genetic testing for aneuploidy (PGT-A) often wish to know how many eggs will be required to optimize the chances of a live birth. However, no precise data on this can yet be provided during genetic counseling for this procedure. On the basis of PGT-A data from related studies and current databases, we have estimated that the number of zygotes required for a 50% chance of a live birth is 8 at age 40 but increases markedly to 21 at age 43. PGT-A markedly reduces the miscarriage rate per embryo transfer but does not alleviate the extremely high number of zygotes required for a live birth in women of an advanced maternal age. Detailed genetic counseling will therefore be desirable prior to undergoing this procedure.