| Risk factors | Patients n (%) |
| Polyhydramnios | 2 (4) |
| Operative delivery | 8 (16) |
| Multiple pregnancy | 1 (2) |
| Failed induction or prolonged labor | 20 (40) |
| Preeclampsia | 1 (2) |
| Primiparous | 9 (18) |
| Placental location anomaly | 5 (10) |
| Macrosomia | 3 (6) |
| Advanced maternal age | 10 (20) |
| Previous cesarean section | 7 (14) |
| Maternal obesity | 5 (10) |
| A history of postpartum hemorrhage | 4 (8) |