Risk index for pre-eclampsia
| Risk index score | Prevalence of pre-eclampsia, % | |
| Twin pregnancies | Singleton pregnancies | |
| 0 | 7.2 | 2.0 |
| 1 | 13.5 | 4.1 |
| 2 | 17.8 | 6.5 |
| 3 | 20.0 | 10.1 |
| 4 | 30.8 | 13.4 |
Risk index score is the number of risk factors present among the following: maternal age ≥35 years, nulliparity, diabetes type 1, 2 or gestational diabetes, BMI >29 kg/m2.
BMI, body mass index.