A prospective randomized clinical trial comparing 150 IU and 225 IU of recombinant follicle-stimulating hormone (Gonal-F*) in a fixed-dose regimen for controlled ovarian stimulation in in vitro fertilization treatment.

Objective: To compare fixed daily doses of the recombinant FSH (rFSH) Gonal-F (150 IU vs. 225 IU) for ovarian stimulation in IVF-ET.

Design: Single-center prospective, randomized study. Assisted conception unit of a university hospital. One hundred twenty-four women aged 23-41 years participated in the study. Exclusion criteria were as follows: FSH of >10 IU/L, polycystic ovarian syndrome, one ovary or previous ovarian surgery, previous poor response to ovarian stimulation, or ovarian hyperstimulation syndrome (OHSS).

Intervention(s): Randomized to commence 150 IU or 225 IU of Gonal-F per day without dose alterations during treatment.

Main Outcome Measure(s): Number of oocytes retrieved and total rFSH dose.

Result(s): More oocytes were retrieved in women aged or=33 years), the number of oocytes retrieved in the two groups were similar. No significant differences were found for fertilization rate, number of embryos formed and cryopreserved, and pregnancy rates between the two groups. The total rFSH dose used was higher in the 225-IU group (2,595.0 +/- 510.0 vs. 1,897.5 +/- 457.5 IU). The cancellation rate due to insufficient ovarian response was higher in the 150-IU group (15.0% vs. 3.3%). All cases of ovarian hyperstimulation syndrome (n = 4) occurred in the 225-IU group.

Conclusion(s): Two hundred twenty-five IU is more effective than 150 IU in younger women but requires a higher total dose of Gonal-F. The use of 225 IU in older women did not result in a higher oocyte yield, suggesting that 225 IU of rFSH does not compensate for the age-related decline in the number of follicles available for stimulation.