Distribution (percentages) of maternal characteristics according to cumulative daily loads lifted at work
| No lifting | 15–50 kg | 51–100 kg | 101–200 kg | 201–500 kg | 501–1000 kg | >1000 kg | Total | |
|---|---|---|---|---|---|---|---|---|
| N=46 199 | N=5326 | N=3396 | N=3342 | N=3043 | N=1022 | N=475 | N=62 803 | |
| 73.6 | 8.5 | 5.4 | 5.3 | 4.9 | 1.6 | 0.8 | 100.0 | |
| Maternal age | ||||||||
| <25 years | 9.1 | 16.2 | 15.6 | 17.2 | 17.4 | 18.9 | 21.4 | 11.1 |
| 25–29 years | 40.8 | 43.6 | 44.3 | 42.7 | 40.7 | 42.8 | 39.5 | 41.3 |
| 30–34 years | 37.5 | 30.9 | 30.7 | 30.1 | 31.5 | 29.2 | 29.8 | 35.7 |
| >34 years | 12.7 | 9.3 | 9.4 | 10.1 | 10.4 | 9.1 | 9.2 | 11.9 |
| Missing | N=0 | N=0 | N=0 | N=0 | N=0 | N=0 | N=0 | N=0 |
| Parity | ||||||||
| 0 | 52.7 | 52.6 | 48.7 | 44.7 | 41.1 | 40.5 | 39.7 | 51.2 |
| ≥1 | 47.3 | 47.4 | 51.3 | 55.3 | 59.0 | 59.5 | 60.3 | 48.8 |
| Missing | N=23 | N=3 | N=1 | N=1 | N=0 | N=3 | N=0 | N=31 |
| Cervical cone biopsy | ||||||||
| Yes | 2.0 | 1.7 | 1.9 | 1.7 | 1.9 | 2.1 | 2.5 | 1.9 |
| No | 98.0 | 98.3 | 98.2 | 98.3 | 98.1 | 98.0 | 97.5 | 98.1 |
| Missing | N=2 | N=1 | N=0 | N=1 | N=0 | N=0 | N=0 | N=4 |
| IVF/ICSI treatment | ||||||||
| Yes | 2.6 | 1.9 | 1.2 | 1.6 | 1.9 | 2.0 | 2.9 | 2.4 |
| No | 97.4 | 98.1 | 98.8 | 98.4 | 98.1 | 98.1 | 97.1 | 97.6 |
| Smoking during pregnancy | ||||||||
| Yes | 12.1 | 15.9 | 18.7 | 20.5 | 23.6 | 28.5 | 32.2 | 14.2 |
| No | 87.9 | 84.1 | 81.3 | 79.5 | 76.4 | 71.5 | 67.8 | 85.8 |
| Missing | N=21 | N=4 | N=3 | N=0 | N=0 | N=0 | N=1 | N=29 |
| Pre-pregnancy BMI | ||||||||
| <18.5 | 4.,4 | 3.6 | 4.1 | 3.7 | 4.1 | 3.9 | 4.3 | 4.2 |
| 18.5–<25 | 70.7 | 65.9 | 64.6 | 63.2 | 59.8 | 57.9 | 54.4 | 68.7 |
| 25–<30 | 18.3 | 22.0 | 21.2 | 21.7 | 22.9 | 23.1 | 27.4 | 19.4 |
| ≥30 | 6.6 | 8.5 | 10.1 | 11.4 | 13. 2 | 15.1 | 14.0 | 7.7 |
| Missing | N=740 | N=84 | N=43 | N=55 | N=48 | N=10 | N=5 | N=985 |
| Psychological stress at work | ||||||||
| Often | 15.9 | 19.9 | 21.3 | 25.4 | 28.1 | 28.8 | 24.2 | 17.9 |
| Now and then/rarely | 84.1 | 80.1 | 78.7 | 74.6 | 71.9 | 71.2 | 75.8 | 82.1 |
| Missing | N=33 | N=3 | N=1 | N=2 | N=1 | N=0 | N=0 | N=40 |
| Work week | ||||||||
| Part time | 21.0 | 30.1 | 31.4 | 31.3 | 29.0 | 27.6 | 16.6 | 23.4 |
| Full time | 79.0 | 69.9 | 68.6 | 68.7 | 71.0 | 72.4 | 83.4 | 76.6 |
| Missing | N=21 | N=3 | N=1 | N=0 | N=0 | N=0 | N=0 | N=25 |
| Lifting >20 kg daily outside work | ||||||||
| Yes | 5.5 | 9.0 | 8.9 | 10.1 | 11.6 | 12.5 | 12.2 | 6.7 |
| No | 94.5 | 91.0 | 91.1 | 89.9 | 88.4 | 87.5 | 87.8 | 93.3 |
| Missing | N=41 | N=5 | N=1 | N=2 | N=4 | N=1 | N=0 | N=54 |
| Predominant work posture | ||||||||
| Standing/walking | 17.8 | 45.5 | 53.3 | 57.9 | 58.1 | 68.2 | 76.1 | 27.4 |
| Other | 82.2 | 54.5 | 46.7 | 42.1 | 42.0 | 31.8 | 24.0 | 72.6 |
| Missing | N=28 | N=1 | N=0 | N=3 | N=4 | N=0 | N=0 | N=36 |
| Primigravidity | ||||||||
| Yes | 59.8 | 59.2 | 63.7 | 65.8 | 69.8 | 70.7 | 72.1 | 61.0 |
| No | 40.2 | 40.8 | 36.3 | 34.3 | 30.2 | 29.4 | 27.9 | 39.0 |
| Missing | N=22 | N=3 | N=1 | N=1 | N=0 | N=3 | N=0 | N=30 |
| Gestational duration | ||||||||
| 22–27+6 weeks | 0.2 | 0.2 | 0.2 | 0.1 | 0.3 | 0.2 | 0.6 | 0.2 |
| 28–32+6 weeks | 0.6 | 0.5 | 0.5 | 0.9 | 0.9 | 0.8 | 1.0 | 0.7 |
| 33–36 +6 weeks | 3.6 | 3.6 | 4.0 | 4.0 | 4.1 | 3.2 | 4.5 | 3.7 |
| 37+weeks | 95.3 | 95.3 | 95.1 | 94.9 | 94.5 | 95.8 | 93.6 | 95.4 |
| Missing | N=29 | N=1 | N=4 | N=4 | N=6 | N=1 | N=1 | N=46 |
62 803 women in the Danish National Birth Cohort, 1996–2002.
BMI, body mass index.