**4.1 Abnormal placentation**

In addition, 59.8% of patients with adherent placenta and 75% with placenta previa have a history of previous cesarean section. The high incidence of PH is directly related to the increasing number of cesarean sections [15]. It has been reported that the incidence of placenta previa after one previous cesarean section increases by 47-fold in patients with four previous cesarean section [1]. Similarly, patients with previous surgical abortions were found to be more likely to have abnormal placentation. The risk is even higher in patients with multiple surgical abortions [16].


#### **Table 3.** *Independent risk factors for uterine atony.*

Patients with only placenta previa have 16% risk of undergoing PH, but this risk rises up to 16% in patients with placenta previa and scarred uterus [17].
