| Parameters | Risk Score | |||
| 1 | 2 | 3 | 4 | |
| Age (years) | <40 | ≥40 | - | - |
| Previous pregnancy | Mola | Abortion | Term pregnancy | - |
| Interval (months) between the previous pregnancy and NTG | <4 | 4 - 6 | 7 - 12 | >12 |
| hCG (UI/L) NTG pretreatment | <10,000 | <10,000 - <100,000 | >100,000 - 1,000,000 | >1,000,000 |