Placenta accreta

Placenta accreta occurs when all or part of the placenta attaches abnormally to the myometrium (the muscular layer of the uterine wall). Three grades of abnormal placental attachment are defined according to the depth of invasion: Accreta — chorionic villi attach to the myometrium, rather than being restricted within the decidua basalis. Increta — chorionic villi invade into the myometrium. Percreta — chorionic villi invade through the myometrium.