The first case series of abnormally adherent placenta (AAP) was published in 1937 by Irving and Hertig. They reviewed 18 cases, which they described clinically as “the abnormal adherence of the after birth in whole or in parts to the underlying uterine wall” and histologically as “the complete or partial absence of the decidua basalis”, signs that are still used by pathologists today. They described all their cases as “Vera” or “adherent” where the villi were attached to the surface of the myometrium without invading it.
The grading classification of abnormally adherent placenta (AAP) according to the depth of villous invasiveness inside the myometrium was introduced by pathologists in the 1960s (Luke et al., 1966). They separated PA into 3 categories:
1. Placenta accretes (PA) when the villi simply adhere to the myometrium.
2. Placenta increate (PI) when the villi invade the myometrium.
3. Placenta percreta (PP) when the villi invade the full thickness of the myometrium.
Placenta accrete must be supposed in women who have both a placenta praevia, particularly anterior and a history of cesarean or further uterine operation. The most significant factor affecting outcome is the prenatal diagnosis of this circumstance. It gives the chance to make a delivery chart that correctly anticipates the predictable blood loss and other probable complications of delivery. In addition, it gives the chance for electively timing the process since avoidance of complications perfectly requires the presence of a multidisciplinary surgical team,. Comstock CH. (2005).
At this occasion, no antenatal diagnostic method gives the clinician 100% assurance of either ruling in or ruling out the existence of placenta accrete. The definitive diagnosis of placenta accrete is frequently ended postpartum on hysterectomy specimens when an area of accretion shows chorionic villi direct make contact with the myometrium and absence of deciduas ,Tantbirojn P.,et al , (2008).