Corifollitropin Alfa on D5 Versus D7 After Contraceptive Pill

Inclusion Criteria: * Women 18-35 y old ,with regular spontaneous menstrual cycles of 25-30 days length * Who had vaginal sexual intercourse or have no inconvenient for vaginal explorations * Donors can´t have more than 6 children (neither own or after donations) * Not be adopted or being born after a gamete donation pregnancy * BMI between 18-28 kg/m2 * Height \> 1.55cm * Gynecological and general examination with Pap smear, HIV, HCV (hepatitis C virus ), HBV (hepatitis B virus ) and RPR(rapid plasma reagin test ) negative serology, and with normal karyotype * No abnormal Psychological profile * Discard any disease: blood disorders, neurodegenerative/psychiatric diseases, Fragile X Syndrome, cystic fibrosis carrier, oncology diseases. * Without psychological/psychiatric family history * Will conform to the protocol for the duration of the study * Willingness of adhesion to protocol during the whole study period * Signed informed consent Exclusion Criteria: * Polycystic ovarian syndrome * Antral follicle count \> 20 * Hypersensitivity to the active substance or any of the excipients * Abnormal vaginal bleeding of unknown ethiology * Presence of ovarian cysts or increased size ovaries * History of ovarian hyperstimulation syndrome * Previous controlled ovarian stimulation cycle with more than 30 follicles ≥ 11mm * Previous abdominal surgery that contraindicated the practice of follicular puncture * HIV, HCV, HBV positive serology in women or partner * Important systemic diseases that could interfere with gonadotrophin treatment (ovarian and hypothalamic tumors…)