Late postpartum hemorrhage is most commonly caused by retained placenta and membranes. About ten days after childbirth, the patient may experience significant bleeding due to the degeneration and necrosis of the retained placental and membrane tissues within the uterine cavity. When these necrotic tissues are shed, it can cause the blood vessels to open and lead to bleeding. Additionally, poor healing of the placental site on the uterus can also cause bleeding, as can infections, with endometritis being relatively common. Inflammation can lead to poor healing of the placental attachment site or poor uterine contraction, resulting in significant uterine bleeding.