decidua /disij″o̅o̅·ə/ [L, decidere, to fall off] , the epithelial tissue of the endometrium lining the uterus. It envelops the conceptus during gestation and is shed in the puerperium. It is also shed periodically with menstruation. Kinds include decidua basalis, decidua capsularis, decidua vera. See also amniotic sac.
