What is a common cause of sudden late onset postpartum hemorrhage?

Retained placental fragments are a significant cause of sudden late-onset postpartum hemorrhage. After delivery, it is essential for the entire placenta to be expelled from the uterus. If fragments remain inside, they can prevent the uterus from contracting effectively, leading to uterine atony and subsequent bleeding. This condition may manifest days or even weeks after childbirth, making it a common concern during the late postpartum period. The retained tissue can also become necrotic, which further exacerbates bleeding as it interferes with the body's natural processes to restrict blood flow to the area.

In contrast, increased uterine contraction activity can typically help prevent hemorrhage by ensuring that the uterus contracts effectively and expels any remaining tissue. Weakness in the uterine musculature may contribute to hemorrhage, but typically in the early postpartum period rather than as a sudden late-onset situation. Necrotic tissue separation, while of concern in certain scenarios, is not a primary factor in late postpartum hemorrhage compared to the impact of retained placental fragments. Understanding this helps clarify the crucial role that retained placental tissue plays in postpartum complications.