Endometrial Gene Expression Profiles During Ovarian Stimulation With Recombinant FSH With or Without the Addition of Recombinant LH in Genuine Poor Responders

This is a prospective randomized open-label cross-over study, in which patients will be randomized to either start in the control group or in the study group. Participants will undergo both treatments with an interval of minimum 1 and maximum 6 months. In both treatment arms, ovarian stimulation will be started at day 2/3 of the menstrual cycle. In the control group, 225 IU of recombinant FSH will be administered in a fixed antagonist protocol. In the study group, 225 IU of recombinant FSH plus 112,5 IU of recombinant LH will be administered. Cycle monitoring will be performed through serum estradiol (E2), progesterone (P), and luteinizing hormone (LH) assessments, combined with serial ultrasound examinations. Both groups will undergo dual triggering with gonadotropin releasing hormone agonist (GnRHa) 0,2ml and human chorionic gonadotrophin (hCG) 6500IU if one or more follicles of ≥ 17 mm are observed. The oocyte retrieval (OR) will be performed between 34 and 36 hours after final oocyte maturation trigger. At each OR, follicles will be individually meas-ured, aspirated and searched for the presence of cumulus oocyte complexes (COC). Metaphase II (MII) oocytes will then be injected to standard intra-cytoplasmatic sperm injection (ICSI) procedures. In both groups, a freeze-all strategy will be applied. An endometrial biopsy (Pipelle de Cornier ®) will be taken 7 days after final oocyte maturation trigger. After completion of both treatment cycles, a frozen embryo transfer of a single embryo will be performed.