Treg/CD4 Tconv cell proportions in human endometrium have not been previously clearly defined,32 there is limited evidence of increased FOXP3+ cells (immunohistochemical analysis) in the endometrium of RPL patients,33 but Tconv and Treg proportions and populations have mainly been studied in in the peripheral blood or decidua obtained after miscarriage. This evidence concerns the gene FOXP3 and spontaneous abortion.