ABSTRACT
Decidua basalis (DB) is the decidua at the maternal surface of the placental disk, decidua capsularis (DC) is the decidua attached to the free membranes of the protruding embryo, and decidua parietalis (DP) or decidua vera is the decidua lining the uterine cavity. The DC fuses with the DP at about 17 weeks’ gestation when the membranes come into contact with the uterine wall, largely obliterating the uterine cavity.
