Postpartum hemorrhage (PPH) is a leading cause of death and morbidity relating to pregnancy. Uterine atony is the leading cause of PPH, and trauma, including iatrogenic trauma, increases the risk for postpartum hemorrhage. Women with PPH in a pregnancy are at increased risk of PPH in a subsequent pregnancy. Awareness of these facts, and anticipation and prevention of uterine atony, as well as avoiding unnecessary cesareans, episiotomies, and other genital tract trauma have the potential to significantly reduce the mortality and morbidity from postpartum hemorrhage. The epidemiology of postpartum hemorrhage, including the incidence and temporal trends as well as the causes and risk factors associated with it are presented.