What is postpartum hemorrhage and what are the risk factors?

Postpartum hemorrhage is defined as blood loss exceeding 1,000 milliliters or blood loss accompanied by signs of hypovolemia. The most common cause is uterine atony, where the uterus fails to contract firmly after delivery. Risk factors include overdistended uterus from multiple gestation, polyhydramnios, or macrosomia; prolonged labor; rapid labor; multiple previous pregnancies; magnesium sulfate use; and chorioamnionitis. The nurse assesses fundal firmness every 15 minutes in the first hour. A boggy uterus requires immediate fundal massage.