Regression model for birth length (F=14.2, p<0.0001, r2=0.10)
| β coefficient | p value | |
| Intercept | 50.0 | 0.0001 |
| Parity | 0.2 | 0.0001 |
| Gestational age | 0.3 | 0.0001 |
| Parental social group | −0.2 | 0.01 |
| Birth cohort8-150 and site=home | 0.002 | 0.98 |
| Birth cohort8-150 and site=hospital | 0.3 | 0.006 |
↵8-150 Where birth cohort 0=1918, 1=1922, 2=1930.