The success of assisted reproductive technologies (ART) is critically dependent on optimizing protocols for controlled ovarian stimulation to provide adequate numbers of good quality oocytes and embryos. This optimization is mainly valuable to a group of infertility patients (9%-24%) who respond poorly to Controlled Ovarian Stimulation(COS). It is also important for an additional 2.6% of the infertility patients who manifest a high response to gonadotropin and are at risk for hyperstimulation syndrome, a life-threatening situation. Extensive research was carried out and led to the introduction of GnRH antagonist, as an alternative to GnRH agonist, for the prevention of premature LH surges. Further research to optimize the GnRH antagonist regimen concluded that a daily treatment with 200 IU of recFSH in a GnRH antagonist regimen is safe, well tolerated and results in a good clinical outcome. This protocol is now frequently applied in the US and Europe.

Predicting a woman's response (based on the assessment of ovarian reserve) to COS is useful in determining individualized clinical management strategies for low and high responders and thus avoiding cancellation. Such prediction when based on reliable scientific evidence is valuable in consulting patients about their chances of success. A large number of studies have been performed, which used certain clinical, ultrasonographic and hormonal markers (called predictive factors), to try to optimize a COS protocol for patients who were down-regulated with a long GnRH agonist protocol. Prospective trials of predictive models have also been used to adjust the starting dose of FSH to prevent a too low or too high ovarian response. To date, however, none have been performed for women undergoing ovarian stimulation with a GnRH antagonist protocol.

The primary objective of this randomized, open-label, multicenter clinical trial was to identify one or more factors capable of predicting ovarian response in women treated with a daily dose of 200 IU recFSH in a GnRH antagonist protocol. Since many ART centers now use oral contraceptives as a means to schedule patients stimulated with recFSH and a GnRH antagonist for assisted reproduction, the trial evaluated also whether intervention with oral contraceptives affects the accuracy of predictive models for ovarian response.