FSH receptor genotype and its influence on the results of donor ovarian stimulation using corifollitropin alfa

Research question Does the FSH receptor (FSHR) genotype influence the results of donor ovarian stimulation using corifollitropin alfa? Design A prospective cohort study was performed including 152 oocyte donor ovarian stimulations: group 1 (n = 80) using a single dose of 150 µg of corifollitropin alpha; and group 2 (n = 72) using in addition to corifollitropin alpha, continued stimulation using recombinant FSH 225 IU daily. Allelic discrimination was used to genotype the FSHR p.N680S polymorphism. Linear regression analysis was performed to study the differences between groups. Results No differences in clinical characteristics between genotypes were reported. Overall, the results of ovarian stimulation were better in oocyte donors with SN and NN genotypes compared with SS in terms of the number of retrieved oocytes (15.78 versus 10.83; P = 0.008) and retrieved metaphase II (MII) oocytes (12.34 versus 9.00; P = 0.032). Corresponding differences were also observed in group 1 for the number of retrieved oocytes (13.83 versus 7.50, P = 0.018) and retrieved MII oocytes (10.24 versus 5.42; P = 0.038). However, in group 2 no significant differences were found for oocytes retrieved (17.55 versus 13.06, P = 0.064) or MII oocytes (14.25 versus 11.39; P = 0.12). Conclusions This study suggests that ovarian stimulation protocols with corifollitropin alfa in women with the SS genotypes could be associated with fewer oocytes and MII oocytes retrieved. Despite the fact that corifollitropin alfa has a longer half-life, the results for the SS genotype do not match those for the other genotypes, so other factors must be involved. Therefore, to tailor treatments, it would be advisable to genotype women at p.N680S of the FSHR.