Prospective cohort study in high responder oocyte donors using two hormonal stimulation protocols: impact on embryo...

Ovarian stimulation regimens for in vitro fertilization seem to have a deleterious effect on oocyte quality and embryo aneuploidy in a dose-dependent manner. This study aims to test the influence of gonadotrophin doses on embryo aneuploidy rates.

A total of 32 young oocyte donors with a high response to ovarian stimulation, were included in the study. Two subsequent stimulation treatments were performed in each donor: first, a standard dose cycle using a 225 IU starting dose of recombinant FSH (r-FSH) and secondly, a reduced dose cycle with a starting dose of 150 IU r-FSH. In both cycles, GnRH agonist co-treatment was used for down-regulation. Ovarian response, embryo development and aneuploidy for chromosomes 13, 15, 16, 17, 18, 21, 22, X and Y were the main outcomes of the study.

A total of 22 donors completed both treatments with different gonadotrophin doses. In the remaining 10 donors, the reduced dose cycle was cancelled due to low ovarian response. In those donors who completed both regimens, significant increases in rates of fertilization and chromosomally normal blastocysts were observed in the reduced dose cycle. No differences were observed in pregnancy and implantation rates in recipients who received oocytes from standard and reduced doses cycles.

Despite the limited numbers in our study, we can conclude that in high responder donors, a decrease in the gonadotrophin dose could improve fertilization rates and embryo quality. However, due to the reduced oocyte numbers with lower doses, a similar reproductive outcome in terms of live births would be expected.