chronic deciduitis chronic deciduitis chronic deciduitis is a type of long-lasting inflammation that arises in pregnancy and affects the endometrial stromal tissue (decidua). chronic deciduitisother namesplasma cell deciduitismicrograph of a chronic deciduitis, showing the characteristic plasma cells. h&e stain. it is associated with preterm labour. the diagnosis rests primarily on the presence of plasma cells. intermed. mag. high mag.