Background Recurrent spontaneous abortion (RSA) is commonly attributed to immune dysregulation at the maternal–fetal interface. The contribution of the spleen, as a peripheral immune organ, remains unclear. This study investigated spleen-associated immune alterations in a murine model of RSA. Methods An RSA model was established by mating CBA/J females with DBA/2 males. Splenic and decidual immune-cell distributions were asses...