| Gestational age | MRI over US | P-value | ||||
| Minimum to maximum | Range |
| Add | Change diagnosis | Confirm | |
| 20 to 32 weeks | 26 ± 4.5 weeks | >24 weeks <24 weeks | 10 (16.6%) 0 | 5 (8.3%) 0 | 18 (30%) 27 (45%) | 0.016 |