Table 3.
Maternal occupational exposure* to welding fumes and small for gestational age (SGA)†, low birth weight (LBW)‡ and preterm birth (PTB)§ subdivided by work participation during pregnancy
| Working full time with low absence from work¶ | Working full or part time with moderate absence from work** | Working full or part time with high absence from work†† | ||||||||||
| Crude | Adjusted‡‡ | Crude | Adjusted‡‡ | Crude | Adjusted‡‡ | |||||||
| (n=376 831) | (n=370 126) | (n=418 233) | (n=410 370) | (n=200 779) | (n=196 878) | |||||||
| OR (95% CI) | No of cases | OR (95% CI) | No of cases | OR (95% CI) | No of cases | OR (95% CI) | No of cases | OR (95% CI) | No of cases | OR (95% CI) | No of cases | |
| SGA | ||||||||||||
| No exposure | 1 | 8916 | 1 | 8729 | 1 | 8097 | 1 | 7913 | 1 | 2982 | 1 | 2908 |
| Low exposure | 1.63 (1.34 to 1.99) | 106 | 1.45 (1.19 to 1.78) | 103 | 1.29 (1.05 to 1.59) | 94 | 1.14 (0.92 to 1.40) | 92 | 1.21 (0.90 to 1.64) | 44 | 1.03 (0.76 to 1.40) | 44 |
| High exposure | 1.14 (0.91 to 1.43) | 77 | 1.05 (0.83 to 1.32) | 76 | 1.18 (0.95 to 1.47) | 83 | 1.07 (0.86 to 1.34) | 81 | 1.15 (0.85 to 1.54) | 46 | 0.94 (0.69 to 1.26) | 45 |
| LBW | ||||||||||||
| No exposure | 1 | 13 362 | 1 | 13 109 | 1 | 10 104 | 1 | 9867 | 1 | 4188 | 1 | 4068 |
| Low exposure | 1.75 (1.49 to 2.05) | 168 | 1.52 (1.30 to 1.79) | 166 | 1.13 (0.93 to 1.38) | 103 | 1.06 (0.87 to 1.29) | 102 | 1.00 (0.75 to 1.32) | 51 | 0.87 (0.65 to 1.16) | 49 |
| High exposure | 1.37 (1.15 to 1.63) | 137 | 1.22 (1.02 to 1.45) | 134 | 1.08 (0.88 to 1.33) | 95 | 1.00 (0.81 to 1.23) | 93 | 1.14 (0.88 to 1.46) | 64 | 0.99 (0.76 to 1.27) | 62 |
| PTB | ||||||||||||
| No exposure | 1 | 21 451 | 1 | 21 066 | 1 | 16 109 | 1 | 15 753 | 1 | 7586 | 1 | 7389 |
| Low exposure | 1.36 (1.18 to 1.56) | 211 | 1.16 (1.00 to 1.34) | 205 | 0.98 (0.82 to 1.16) | 142 | 0.92 (0.77 to 1.09) | 138 | 1.08 (0.89 to 1.33) | 100 | 0.99 (0.81 to 1.22) | 97 |
| High exposure | 1.38 (1.20 to 1.58) | 220 | 1.24 (1.07 to 1.42) | 216 | 0.87 (0.72 to 1.04) | 122 | 0.82 (0.68 to 0.98) | 119 | 1.01 (0.83 to 1.23) | 103 | 0.93 (0.76 to 1.14) | 101 |
*Exposure divided into unexposed (0), low exposure (>0–50th percentile) and high exposure (>50th percentile). The 50th percentile=0.09 mg/m3.
†Small for gestational age, estimated by a calculated growth curve of weight and gestational age.
‡Low birth weight, dichotomised as <2500 g and ≥2500 g.
§Preterm birth, dichotomised as <37 weeks and ≥37 weeks.
¶Full-time workers who stated that they were working full time at the interview in week 10 and had fewer than 50 days of absence from work (<50th percentile) during pregnancy (excluding the first 14 days of sickness).
**Part-time workers who stated that they were working part time at the interview in week 10 or had 50 or more days (≥50th percentile) but fewer than 112 days of absence from work (<75th percentile) during pregnancy (excluding the first 14 days of sickness).
††All workers who responded to the question about work at the interview in week 10 and had 112 or more days of absence from work (≥75th percentile) during pregnancy, except those who stated that they were not working at all.
‡‡ OR adjusted for mothers’ age, education, smoking habits, nationality, occupational exposure to noise and parity.