SHorter Treatment of Replacement Therapy for Frozen Embryo Transfer (FET)

This is a Single-centre pilot study, randomized, controlled open-label trial with the aim to assess the clinical pregnancy rate and the early pregnancy loss rate between two different schemas for frozen embryo transfer cycles stimulated with HRT. Furthermore, the investigators would like to evaluate the predictivity of pregnancy and early miscarriage by looking at the endocrinological profile (estradiol and progesterone levels) within the endometrial preparation and the day of embryo transfer (ET).