Table 1.

FIGO clinical and histologic criteria for PAS.

Adapted from Jauniaux et al.¹⁸.

	Clinical criteria	Histologic criteria
Grade 1	Attempts at manual removal of adherent placenta results in heavy bleeding requiring mechanical or surgical measures	Hysterectomy specimen with extended areas of absent decidua between villous tissue and myometrium
Grade 2	Macroscopic findings: hypervascularity, placental bulge, “dimple sign”	Hysterectomy specimen shows placental villi within muscular fibers
Grade 3	Macroscopic findings of Grade 2 AND placental villi seen to be invading through uterine surface ± invasion into other pelvic structures	Hysterectomy specimen showing villous tissue breaching the uterine serosa