Which one of the following is not a cause of secondary postpaum hemorrhage?

- Placenta pre causes APH Secondary postpaum hemorrhage is bleeding after 24 hours to 12 weeks after delivery. Causes of PPH : Uterine atonicity ( most common cause of primary PPH) Injury to any pa of genital tract Coagulopathy (von Willebrand's disease) Retained tissues - (most common cause of secondary PPH ) Usually, retained products undergo necrosis with fibrin deposition and may eventually form a so-called placental polyp.