Fig. 3

A study flow chart in pregnant patients with placenta previa. All patients with placenta previa were performed cesarean section (CS) (*). Retained products of conceptions (RPOC) (**) was diagnosed using ultrasonography (US), contrast-enhanced computed tomography (CT), and contrast-enhanced magnetic resonance imaging (MRI) according to previous reports until seven days after CS. Severe postpartum hemorrhage (severe PPH) (***) was defined as > 1000 ml of blood loss within 24 h of CS