|
| Controls n = 855 | Preterm delivery cases n = 299 | |||
|
| n | %^ | n | %^ | Unadjusted OR [95% CI] |
| Maternal characteristics |
|
|
|
|
|
| Maternal age (years) |
|
|
|
|
|
| ≤20 | 13 | 1 | 7 | 2 | 1.52 [0.59 - 3.90] |
| 21 - 30 | 333 | 39 | 118 | 39 | 1.00 [Reference] |
| 31 - 40 | 495 | 58 | 162 | 54 | 0.92 [0.70 - 1.22] |
| >40 | 13 | 1 | 12 | 4 | 2.60 [1.16 - 5.87] |
| Partner |
|
|
|
|
|
| Yes | 816 | 96 | 279 | 94 | 1.00 [Reference] |
| No | 34 | 4 | 19 | 6 | 1.63 [0.92 - 2.91] |
| Education |
|
|
|
|
|
| Primary/middle school | 246 | 29 | 87 | 29 | 1.00 [Reference] |
| High school | 417 | 49 | 142 | 47 | 0.96 [0.71 - 1.31] |
| University | 191 | 22 | 69 | 23 | 1.02 [0.71 - 1.50] |
| Working activity during the last three months |
|
|
|
|
|
| No | 240 | 29 | 86 | 29 | 1.00 [Reference] |
| Yes | 587 | 71 | 204 | 70 | 0.97 [0.72 - 1.30] |
| Reproductive history |
|
|
|
|
|
| Newborn sex |
|
|
|
|
|
| Males | 413 | 48 | 160 | 54 | 1.00 [Reference] |
| Females | 442 | 52 | 135 | 46 | 0.79 [0.60 - 1.03] |
| Parity |
|
|
|
|
|
| Primiparae | 424 | 50 | 153 | 51 | 1.00 [Reference] |
| Multiparae | 428 | 50 | 145 | 49 | 0.94 [0.72 - 1.22] |
| Previous preterm deliveries§ |
|
|
|
|
|
| No | 386 | 91 | 99 | 68 | 1.00 [Reference] |
| Yes | 38 | 9 | 46 | 32 | 4.72 [2.91 - 7.65] |
| Previous SGA§ |
|
|
|
|
|
| No | 343 | 96 | 73 | 74 | 1.00 [Reference] |
| Yes | 15 | 4 | 26 | 26 | 8.14 [4.11 - 16.14] |
| Miscarriages§ |
|
|
|
|
|
| No | 285 | 67 | 76 | 52 | 1.00 [Reference] |
| Yes | 140 | 33 | 69 | 48 | 1.85 [1.26 - 2.71] |