Maternal characteristics as risk factors for postpartum hemorrhage are shown in Table 1. There was a slightly increased risk for postpartum hemorrhage among women in all 5-year classes who were older than age 30 years. Primiparous women had an increased risk for postpartum hemorrhage. Smoking seemed to decrease the risk for postpartum hemorrhage. There was an overall slightly increased risk for postpartum hemorrhage with increasing maternal BMI, although it did not reach statistical significance in obesity class III