Subcutaneous Progesterone Versus Vaginal Progesterone for Endometrial Preparation in Fresh Donated Oocytes Recipients

Inclusion Criteria: * Female, aged from 18 to 49 years (both inclusive) * Woman who wishes to become pregnant * Endometrial thickness greater 7 mm on the day of patient randomisation to one of the progesterone groups * Six or more donor retrieved oocytes * Patient programmed for fresh embryo transfer on day +5 of embryo culture * BMI lower than 30 Kg/m2 * Infertility that justifies treatment with donor oocytes * Male with no known karyotype alterations * Semen by ejaculation from either the partner or from a bank * Uterus able to support embryo implantation and pregnancy * Absence of pregnancy before starting the embryo transfer cycle * Has given prior written consent Exclusion Criteria: * \- Important systemic diseases, endocrine-metabolic abnormalities involving the pituitary, thyroid, adrenals, pancreas, liver or kidney. * HIV, HBV or HCV seropositivity * Undiagnosed vaginal bleeding * Pregnancy, breastfeeding or any contraindication to becoming pregnant * Malformation of sexual organs incompatible with pregnancy * Known allergy to progesterone preparations or their excipients * Current dependence on alcohol, drugs or psychotropic medication * Concurrent participation in another study * Concomitant medication that could interfere with the study medication: different hormonal treatments used in the study, except thyroid hormones, antipsychotics, anxiolytics, hypnotics, sedatives, chronic treatment with prostaglandin inhibitors