The effect of maternal BMI on postpartum hemorrhage according to delivery method is shown in Table 3. There was an increased risk for postpartum hemorrhage the heavier the woman was after normal delivery, and it was even more pronounced after instrumental delivery. The trend was the same for cesarean delivery, although it was not statistically significant for women in obesity class I. There seemed to be no effect of BMI on the risk for postpartum hemorrhage after induction of labor, irrespective of
delivery mode. The absolute risk for postpartum hemorrhage in obesity class III was 5.2% for normal vaginal delivery, 13.6% for instrumental delivery, 1.8% for cesarean delivery, and 5.3% after induction of labor. The comparable risks for normal-weight
women were 4.4%, 8.8%, 1.4%, and 5.2%.