Toldi G revealed that the proportion of CD4+ CD25+ Foxp3+ Tregs was lower in preeclampsia patients, which have comparable levels to the non‐pregnant women.31 In pathogen‐induced miscarriage animal model, Foxp3 expression is inhibited in peripheral blood, inguinal lymph nodes, and spleen as well as at the maternal‐foetal interface.32 In spontaneous abortion patients, Foxp3 expression are dramatically reduced in CD4+CD25+ T cells in peripheral blood.33 Our study indicated that Foxp3 expression is suppressed in peripheral blood as well as placenta from FGR patients. Here, FOXP3 is linked to spontaneous abortion.