A

Placenta accreta most commonly develops when the placenta implants over a previous cesarean-section scar, where the decidua is deficient [Miller 1997, PMID 9240608]. In accreta, villi attach to or superficially invade the myometrium; only the more severe percreta stage reaches the serosa [Abdelwahab 2023, PMID 37130375]. Management is usually by leaving the placenta in situ or performing hysterectomy rather than piecemeal removal, and it is not implicated in amniotic fluid embolism.