Why is there so much bleeding with cesarean hysterectomy?

Huge blood supply: Basically the pregnant uterus has a huge blood supply from numerous and very large blood vessels and the organ itself is very large. During surgery for a cesarean hysterectomy each vessel keeps bleeding copiously until it is secured with a suture ligation (stitch). In the nonpregnant state, the blood vessels and uterus are much, much smaller making it easier to secure the bleeding.