Table 1.
Relation between categorized z-scores for PM10 measurements and spontaneous and induced preterm delivery.
| Preterm delivery N (%) | Term delivery* N (%) | |
|---|---|---|
| Spontaneous delivery | ||
| Categorized z-scores for proportion > 55 μg PM10/m3 | ||
| <0 | 76(7.1) | 994 (92.9) |
| [0—1] | 26(3.8) | 661 (96.2) |
| >1 SD | 55(17.9) | 252 (82.1) |
| Categorized z-scores for mean PM10/m3 | ||
| <−1 SD | 33 (9.7) | 307 (90.3) |
| [−1 SD—0] | 47 (6.5) | 673 (93.5) |
| [0—1 SD] | 40 (6.2) | 606 (93.8) |
| >1 SD | 48 (12.3) | 341 (87.6) |
| Induced delivery | ||
| Categorized z-scores for proportion > 55 μg PM10/m3 | ||
| <0 | 101 (15.7) | 543 (84.3) |
| [0—1] | 23 (6.7) | 322 (93.3) |
| >1 SD | 66 (31.4) | 144 (68.6) |
| Categorized z-scores for mean PM10/m3 | ||
| <−1 SD | 42 (19) | 179 (81) |
| [−1 SD—0] | 63 (14.9) | 361 (85.1) |
| [0—1 SD] | 38 (10.7) | 318 (90.3) |
| >1 SD | 63 (28) | 162 (72) |
* > =37 weeks pregnancy.