Table 2. Maternal characteristics of the population.
| Cases (N = 42) | Controls (N = 49) | P | |
| Maternal age (y) | 31.14±5.9 | 32.14±5.4 | 0.41 |
| BMI (kg/m2) | 21.53±3.9 | 22.0±3.2 | 0.51 |
| Primiparity | 83.3 | 69.4 | 0.12 |
| Non-white ethnicity | 26.2 | 20.4 | 0.51 |
| Smoker | 26.2 | 20.4 | 0.51 |
| Superior studies | 43.9 | 51.1 | 0.5 |
| Low -Socio-economic status a | 26.5 | 18.4 | 0.41 |
| GA at US (w) | 37.08±1.06 | 37.2±0.86 | 0.43 |
| GA at MRI (w) | 37.25±1.01 | 37.32±1.01 | 0.75 |
Results are expressed as mean ± and standard deviation or percentage determined by Students t-test for independent samples, Pearson's X 2 or Fisher's exact test as appropriate. Y: years. BMI: Body mass index. GA: Gestational age.US: Ultrasound. MRI: Magnetic Resonance Imaging; w = weeks. a Routine occupations, long-term unemployment, or never worked (United Kingdom National Statistics Socio-economic Classification).