Table 1 Sample characteristics by parity and birthweight for gestational age category (N = 30,705)
Predictors | Primiparae | Multiparae | ||||
|---|---|---|---|---|---|---|
AGA | SGA | LGA | AGA | SGA | LGA | |
Sociodemographics | ||||||
 Maternal age [years] | 27.2 (5.7) | 26.9 (6.0) | 27.3 (5.5) | 30.3 (5.2) | 29.8 (5.5) | 31.1 (4.9) |
 Common-law/married | 66% | 63% | 67% | 79% | 68% | 84% |
 Area-level income quintiles | 18/22/23/22/15% | 22/21/24/20/13% | 16/23/22/24/15% | 17/21/23/22/17% | 24/22/22/18/14% | 17/19/24/22/18% |
 Urban residence | 66% | 63% | 67% | 79% | 68% | 84% |
Pregnancy risk factors | ||||||
 Smoking before pregnancy | 25% | 37% | 20% | 24% | 47% | 15% |
 Pre-pregnancy BMI [m/kg2] | 25.5 (6.1) | 24.9 (6.4) | 27.7 (6.8) | 26.4 (6.4) | 24.9 (6.0) | 28.8 (7.2) |
 Pre-existing hypertension | 1% | 2% | 2% | 1% | 2% | 2% |
 Pre-existing diabetes | 1% | 1% | 2% | 1% | 1% | 3% |
Past pregnancy history | ||||||
 Previous gestational diabetes | – | – | – | 3% | 2% | 5% |
 Previous child with BW < 2500 g | – | – | – | 7% | 19% | 3% |
 Previous child with BW > 4080 g | – | – | – | 9% | 3% | 31% |
 Previous caesarean section | – | – | – | 24% | 23% | 29% |
 Previous preterm delivery < 29 wks | – | – | – | 1% | 1% | 1% |
 Previous preterm delivery 29–32 wks | – | – | – | 1% | 2% | 1% |
 Previous preterm delivery 33–36 wks | – | – | – | 5% | 7% | 4% |
 Previous death of neonate ≥500 g | – | – | – | 1% | 1% | 0% |
Current pregnancy | ||||||
 Fetal male sex | 51% | 54% | 52% | 51% | 52% | 50% |
 Weight gain at 26 wks [kg] | 8.9 (3.3) | 7.9 (3.1) | 10.3 (3.8) | 7.8 (3.2) | 6.7 (3.2) | 8.8 (3.5) |
 Smoking during pregnancy | 15% | 27% | 9% | 19% | 41% | 10% |
 Substance use in pregnancy | 3% | 5% | 2% | 2% | 4% | 1% |
 Gestational diabetes | 4% | 6% | 8% | 5% | 5% | 10% |
 Pregnancy-induced hypertension | 2% | 5% | 2% | 1% | 2% | 1% |
 Psychiatric disorder | 11% | 13% | 11% | 12% | 14% | 10% |