Table 1 Characteristics of 4037 pregnancies of female workers in the semiconductor industry
From: The relationship between spontaneous abortion and female workers in the semiconductor industry
| Â | The job held longest | Â | |||
|---|---|---|---|---|---|
FAB (NÂ =Â 2314) | PKG (NÂ =Â 1372) | Clerical worker (NÂ =Â 351) | Total (NÂ =Â 4037) | P-value | |
Age at conception (years) | |||||
 Mean ± SD | 27.7 ± 3.5 | 27.8 ± 3.5 | 29.6 ± 3.1 | 27.8 ± 3.5 | <0.001a |
 Post hoc testb | b | b | a |  |  |
 ≤29 | 1747 (75.5) | 1023 (74.6) | 195 (55.6) | 2965 (73.4) | <0.001 |
 30–34 | 506 (21.9) | 304 (22.2) | 141 (40.2) | 951 (23.6) |  |
 ≥35 | 61 (2.6) | 45 (3.3) | 15 (4.3) | 121 (3.0) |  |
BMI at interview (kg/m2) | |||||
 ≤24.9 | 1911 (82.6) | 1104 (80.5) | 320 (91.2) | 3335 (82.6) | <0.001 |
 ≥25.0 | 403 (17.4) | 268 (19.5) | 31 (8.8) | 702 (17.4) |  |
Level of education at interview | |||||
 High school | 1521 (65.7) | 1000 (72.9) | 81 (23.1) | 2602 (64.5) | <0.001 |
 College/university | 793 (34.3) | 372 (27.1) | 270 (76.9) | 1435 (35.5) |  |
Smoking status at interview | |||||
 Non smoker | 1843 (79.6) | 1114 (81.2) | 341 (97.2) | 3298 (81.7) | <0.001 |
 Smoker | 471 (20.4) | 258 (18.8) | 10 (2.8) | 739 (18.3) |  |
Pregnancy outcome prior to pregnancy | |||||
 Primigravida | 1232 (53.2) | 744 (54.2) | 180 (51.3) | 2156 (53.4) | 0.358 |
 Full term delivery | 784 (33.9) | 426 (31.0) | 124 (35.3) | 1334 (33.0) |  |
 Preterm delivery | 32 (1.4) | 18 (1.3) | 7 (2.0) | 57 (1.4) |  |
 Spontaneous abortion | 200 (8.6) | 137 (10.0) | 24 (6.8) | 361 (8.9) |  |
 Induced abortion | 52 (2.2) | 38 (2.8) | 13 (3.7) | 103 (2.6) |  |
 Stillbirth | 14 (0.6) | 9 (0.7) | 3 (0.9) | 26 (0.6) |  |
Duration of employment at conception (years) | |||||
 Median (IQR) | 7.6 (5.3–10.5) | 8.0 (5.6–10.9) | 7.3 (4.9–10.5) | 7.8 (5.3–10.7) | 0.009c |
 Post hoc testd | a | b | a |  |  |
 ≤4 | 523 (22.6) | 255 (18.6) | 94 (26.8) | 872 (21.6) | 0.004 |
 5–9 | 1123 (48.5) | 685 (49.9) | 154 (43.9) | 1962 (48.6) |  |
 ≥10 | 668 (28.9) | 432 (31.5) | 103 (29.3) | 1203 (29.8) |  |
Year of conception | |||||
 ≥2009 | 1466 (63.4) | 867 (63.2) | 212 (60.4) | 2545 (63.0) | 0.559 |
 ≤2008 | 848 (36.6) | 505 (36.8) | 139 (39.6) | 1492 (37.0) |  |
Study plant | |||||
 A plant | 1369 (59.2) | 740 (53.9) | 274 (78.1) | 2383 (59.0) | <0.001 |
 B plant | 945 (40.8) | 632 (46.1) | 77 (21.9) | 1654 (41.0) |  |
Work schedule | |||||
 Days only | 235 (10.2) | 125 (9.1) | 299 (85.2) | 659 (16.3) | <0.001 |
 Rotating shift | 2079 (89.8) | 1247 (90.9) | 52 (14.8) | 3378 (83.7) |  |