Women’s baseline characteristics
| Characteristic | N | Mean±SD or n (%) |
| Study centre | 1913 | |
| Montreal (8 centres) | 1438 (75.2) | |
| Quebec City | 349 (18.4) | |
| Sherbrooke | 126 (6.6) | |
| Age at first visit, year | 1908 | 31.4±4.5 |
| Prepregnancy BMI, kg/m2 | 1808 | 23.9±5.0 |
| Underweight (<18.5) | 110 (6.1) | |
| Normal weight (18.5–24.9) | 1161 (64.2) | |
| Overweight (25–29.9) | 325 (18.0) | |
| Obese (≥30) | 212 (11.7) | |
| Gestational age at first visit, weeks | 1908 | 11.6±1.8 |
| Maternal ethnic origin | 1909 | |
| Caucasian (white) | 1389 (72.8) | |
| African-American, Asian, Hispanic, First Nation | 447 (23.4) | |
| Multiethnic | 73 (3.8) | |
| Education: completed high school | 1899 | 1867 (98.3) |
| Marital status: married or living with a partner | 1911 | 1816 (95.0) |
| Working before pregnancy (full time or part time) | 1911 | 1569 (82.1) |
| Household income ≥ $60 000 per year | 1830 | 1294 (70.7) |
| Parity (Para) | 1912 | |
| 0 | 1062 (55.5) | |
| 1 | 624 (32.6) | |
| ≥2 | 226 (11.9) | |
| Smoking status | 1860 | |
| Non-smoker (never smoked) | 1247 (67.0) | |
| Ex-smoker | 375 (20.2) | |
| Smoked during first trimester | 238 (12.8) | |
| History of drug use | 1909 | |
| Used or tried before pregnancy | 1005 (52.7) | |
| Used or tried during first trimester | 46 (2.4) | |
| Never tried | 858 (44.9) | |
| Medical history | ||
| Pregestational diabetes | 1907 | 10 (0.5) |
| Pregestational hypertension | 1902 | 20 (1.1) |
| Paternal weight at visit 1, kg | 1450 | 83.8±15.0 |
Data are presented without imputation for missing values.