Ovarian Response to Controlled Ovarian Stimulation Measured Through the Follicular Output Rate (FORT)

Patients will be allocated for convenience into two groups: those who would receive corifollitropin alpha (Group 1) or HMG (Group 2).

Ovarian stimulation protocol will be performed with a single dose of 100 μg (<60 kg) or 150 μg (≥60 kg) of corifollitropin alpha (Elonva, Schering-Plough, Brazil) in group 1, which could be followed by daily administration of HMG beginning on day 8 if necessary; in group 2 150-300 IU/day HMG (menotropin, Menopur, Ferring, Brazil) will be administered, starting on cycle day 3, according to age, AMH level and AFC, plus gonadotropin-releasing hormone antagonist co-treatment (Ganirelix 25 mcg/day, Orgalutran, Schering-Plough, Brazil) in a flexible protocol (at least 1 follicle >14 mm or 3 or more follicles >12 mm). Doses will be adjusted as needed by the patient according to the ultrasound, which is performed with a 6 MHz multifrequency transvaginal probe (Toshiba, Japan). The criterion for HCG administration (5.000 IU Choriomon, Biopharma, Brazil) will be at least three follicles greater than 17 mm, and then, 36 hours later, transvaginal oocyte retrieval was performed. After 3 or 5 days, one or two good-quality embryos will be transferred. It will be performed intracytoplasmic sperm injection (ICSI) instead of conventional IVF when major male factor is presented.

Primary outcome measure is FORT. Secondary outcome measures include number of oocytes retrieved, MII, duration of stimulation, number of embryos, embryo quality and clinical pregnancy rate. Adverse events, such as ovarian hyperstimulation syndrome (OHSS) or drug-related complications are also monitored.