Background characteristics of the study population, comparing those women who were included in the present analysis versus those who were not
| Characteristics | Inclusion in the present analysis | |
| Yes# (n=2528) | No# (n=173) | |
| Maternal age years | 32.4 (20–48)¶ | 31.1 (18–44)¶ |
| Maternal data | ||
| BMI before pregnancy (n=2460) | 23.2 (13.8–45.7) | 23.6 (17.1–44.1) |
| Height cm (n=2491) | 168.0 (147.0–187.0) | 167.4 (147.0–186.0) |
| Weight before pregnancy kg (n=2471) | 65.4 (42.5–126.0) | 64.2 (42.0–116.0) |
| Weight at inclusion kg (n=2498) | 70.2 (44.8–132.7) | 68.0 (45.8–117.0) |
| Previous pregnancy | 1292 (51.1) | |
| Previous pregnancies+ (n=2528) | ||
| 0 | 1236 (48.9) | |
| 1 | 652 (25.8) | |
| 2 | 377 (14.9) | |
| 3 | 143 (5.7) | |
| >3 | 120 (4.8) | |
| Education (n=2350) | ||
| Preliminary school only (9–10 years) | 18 (0.8) | |
| High school only | 239 (10.2) | |
| Higher education <4 years | 758 (32.2) | |
| Higher education ≥4 years | 1324 (56.3) | |
| Other | 2 (0.1) | |
| Unknown | 9 (0.4) | |
| Country of origin (n=2350) | ||
| Norway | 1562 (66.5) | |
| Sweden | 523 (22.3) | |
| Other nordic | 31 (1.3) | |
| Rest of the world | 234 (10.0) | |
| Marital status (n=2350) | ||
| Married | 968 (41.2) | |
| Cohabitant | 1313 (55.9) | |
| Single | 44 (1.9) | |
| Divorced/separated | 1 (0.04) | |
| Other | 24 (1.0) | |
| Living environment (n=2350) | ||
| City (densely populated) | 916 (39.0) | |
| City (less densely populated) | 882 (37.5) | |
| Suburb | 373 (15.9) | |
| Countryside (in village) | 127 (5.4) | |
| Countryside (outside village) | 52 (2.2) | |
Data is presented as mean (min–max) or n (%). BMI: body mass index. #: subjects were included in the present analysis if one or more questionnaires (from 18 weeks and 34 weeks) was completed. Subjects were excluded if questionnaires were not completed. Total pregnancies at 18 weeks available for inclusion was 2701. Total questionnaires completed at 18 weeks was 2350. ¶: p<0.001; +: number of reported pregnancies excluding the current pregnancy.