Microbiome and Endometrial Receptivity in Obese Infertile Women

Inclusion Criteria: * Infertile patients undergoing artificial cycle with HRT. * Normal uterus confirmed by ultrasound (absence of uterine pathology such as submucosal or intramural myomas\> 4 cm that deform cavity, endometrial polyps or Müllerian anomalies, or adnexal as communicating hydrosalpinx). * Negative serological tests for HIV, HBV, HCV, RPR Exclusion Criteria: * Taking prescribed antibiotics or using IUDs or contraceptives 3 months prior to taking the sample. NOTE: Patients who have taken prophylactic antibiotics for ovarian puncture may be included at least 1 month before taking the sample. * Age\> 45 years * Uncorrected uterine pathology, uncorrected hydrosalpinx * Recurrent miscarriage (≥2 spontaneous abortions) or failure of implantation (transfer of 6 embryos in day 3 or 4 blastocysts in a cycle of IVF or donation of oocytes without gestation) * Existence of serious or uncontrolled bacterial, fungal or viral infections that, in the opinion of the principal investigator, could interfere with the participation of the patient in the study or in the evaluation of the results of the study. * Any disease or medical condition that is unstable or could endanger the patient's safety and compliance in the study.