SDHB and abortion: Succinate can also act as an inflammatory signal via HIF-1α to induce IL-1β,34 which can directly promote the motility of first-trimester extravillous trophoblasts.35 We found although the CBA/J × DBA/2 spontaneous abortion mouse model was not accompanied by SDHB overexpression and succinate deficiency in villi tissue (Supplementary Fig. 4a, b), additional supplementation of DMS further increased IL-1β level in mice villi tissue and decreased the embryo resorption in this spontaneous abortion mouse model.