The comparision among euploidy of preimplantation blastocysts in different controlled ovary stimulation (COH) protocols.

Compared with the GnRH-a long protocol, the GnRH-ant protocol was associated with a lower euploidy rate per embryo biopsied. The total gonadotropin dosage, duration of stimulation and number of oocytes retrieved did not appear to significantly influence euploidy rates.