A randomized, double-blind, multicentre clinical trial comparing starting doses of 150 and 200 IU of recombinant FSH in women treated with the GnRH antagonist ganirelix for assisted reproduction

Abstract

Background: Studies with the GnRH antagonist ganirelix in assisted reproduction have indicated that compared with traditional GnRH agonist downregulation protocols, slightly fewer oocytes are retrieved. In this study it was investigated whether an increase in the starting dose of recombinant FSH (rFSH) could compensate for this loss.

Methods: A randomized, double-blind, multicentre clinical trial comparing a starting dose of 150 and 200 IU of rFSH (follitropin beta), in women undergoing treatment with the GnRH antagonist ganirelix.

Results: In total, 257 women were treated with rFSH, of whom 131 received 150 IU and 126 women 200 IU. Overall, 10.3 oocytes were retrieved in the 150 IU group and 11.9 in the 200 IU group (P=0.051). This difference became significant when women with cycle cancellation before HCG administration were excluded. Nearly 500 IU of additional rFSH was given in the high-dose group (2014 versus 1541 IU). In the low-dose group, 4.6 high-quality embryos were obtained compared with 4.5 in the high-dose group. Vital pregnancy rates were similar (31 and 25% in the 150 and 200 IU-treated women, respectively). Serum concentrations of FSH, estradiol and progesterone were significantly higher in the high-dose group at day 6 of rFSH treatment and on the day of HCG administration. In the high-dose group, serum LH concentrations were higher at day 6 of rFSH treatment but lower at the day of HCG administration.

Conclusion: By increasing the starting dose from 150 to 200 IU of rFSH, slightly more oocytes can be retrieved in GnRH antagonist protocols for assisted reproduction. However, because this did not translate into a higher number of high quality embryos, the clinical relevance of such a dose increase may be questioned.