PPOS (Progestin Primed Ovarian Stimulation) and Corifollitropin Alfa (CFA) Cross-over Study

P-CCROSS is a randomized, prospective monocentric phase 4 study with a crossover study design. The aim of the study is to compare patient satisfaction (by means of questionnaires) and treatment compliance with IVF treatment with CFA (corifollitropin alfa) and PPOS (Progestin-Primed Ovarian Stimulation) versus conventional IVF treatment with a recombinant FSH/GnRH antagonist. The study will also compare patients undergoing elective fertility preservation versus PGT-A (pre-implantation genetic testing for aneuploidy) patients.The study will have a crossover design so that patients will receive both forms of treatment. The investigators will also compare the endocrine profile and ovarian response of CFA/PPOS versus rFSH/GnRH ovarian stimulation cycles.