| Method | Chronbach’s α | 95% CI | p |
| Trans-cerebellar diameter | 0.941 | 0.913 - 0.960 | <0.001* |
| Placental thickness | 0.945 | 0.919 - 0.963 | <0.001* |
| Trans-cerebellar diameter and Placental thickness | 0.974 | 0.962 - 0.983 | <0.001* |