Table 1.
Distribution and corresponding odds ratios of cases with vertex and breech presentation according to selected factors. Lombardy, Italy.
| Presentation | Unadjusted logistic regression | Adjusted logistic regression ∗ | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vertix | Breech | 95% CI | 95% CI | |||||||
| N | % | N | % | OR | Lower | Upper | OR | Lower | Upper | |
| Maternal age | ||||||||||
| <25 | 43408 | 97.0 | 1344 | 3.0 | 1+ | 1+ | ||||
| 25–29 | 90850 | 96.6 | 3165 | 3.4 | 1.12 | 1.05 | 1.20 | 1.23 | 1.15 | 1.31 |
| 30–34 | 140980 | 96.1 | 5750 | 3.9 | 1.32 | 1.24 | 1.40 | 1.50 | 1.41 | 1.60 |
| 35–39 | 110433 | 95.9 | 4763 | 4.1 | 1.39 | 1.31 | 1.48 | 1.67 | 1.56 | 1.79 |
| 40+ | 29461 | 95.3 | 1448 | 4.7 | 1.59 | 1.47 | 1.71 | 1.84 | 1.69 | 2.00 |
| Maternal education | ||||||||||
| University | 118047 | 96.1 | 4844 | 3.9 | 1+ | 1+ | ||||
| High school degree | 179993 | 96.1 | 7367 | 3.9 | 1.00 | 0.96 | 1.04 | 1.08 | 1.04 | 1.12 |
| Primary/intermediate school or no education | 116464 | 96.5 | 4247 | 3.5 | 0.89 | 0.85 | 0.93 | 1.09 | 1.04 | 1.14 |
| Citizenship | ||||||||||
| Italian | 293243 | 95.9 | 12379 | 4.1 | 1+ | 1+ | ||||
| Foreign | 123054 | 96.7 | 4146 | 3.3 | 0.80 | 0.77 | 0.83 | 0.95 | 0.91 | 0.99 |
| Albanian | 11036 | 96.6 | 388 | 3.4 | 0.83 | 0.75 | 0.92 | |||
| Chinese | 6277 | 97.5 | 163 | 2.5 | 0.62 | 0.53 | 0.72 | |||
| Egyptian | 7189 | 97.2 | 205 | 2.8 | 0.68 | 0.59 | 0.78 | |||
| Moroccan | 16206 | 97.1 | 478 | 2.9 | 0.70 | 0.64 | 0.77 | |||
| Romanian | 14371 | 95.8 | 623 | 4.2 | 1.03 | 0.95 | 1.11 | |||
| Other | 67975 | 96.7 | 2289 | 3.3 | 0.80 | 0.76 | 0.83 | |||
| Previous delivery | ||||||||||
| 0 | 210014 | 95.2 | 10689 | 4.8 | 1+ | 1+ | ||||
| 1 | 147313 | 97.2 | 4239 | 2.8 | 0.57 | 0.55 | 0.59 | 0.47 | 0.45 | 0.49 |
| 2+ | 51874 | 97.5 | 1311 | 2.5 | 0.50 | 0.47 | 0.53 | 0.40 | 0.37 | 0.43 |
| Previous parity in unidentified number | 6932 | 96.1 | 282 | 3.9 | 0.80 | 0.71 | 0.90 | 0.55 | 0.48 | 0.63 |
| Previous caesarean | ||||||||||
| Nulliparous | 210014 | 95.2 | 10689 | 4.8 | 2.15 | 2.07 | 2.24 | NE | ||
| 0 | 133385 | 97.7 | 3156 | 2.3 | 1+ | 1+ | ||||
| 1 | 38316 | 95.5 | 1821 | 4.5 | 2.01 | 1.89 | 2.13 | 1.81 | 1.70 | 1.93 |
| 2+ | 7808 | 96.4 | 291 | 3.6 | 1.58 | 1.39 | 1.78 | 1.60 | 1.40 | 1.82 |
| Previous spontaneous or induced abortion | ||||||||||
| No | 294791 | 96.1 | 11849 | 3.9 | 1+ | 1+ | ||||
| Yes | 121506 | 96.3 | 4676 | 3.7 | 0.96 | 0.92 | 0.99 | 1.05 | 1.01 | 1.09 |
| Mode of conception | ||||||||||
| Spontaneous conception | 408332 | 96.2 | 15959 | 3.8 | 1+ | 1+ | ||||
| Assisted conception | 7965 | 93.4 | 566 | 6.6 | 1.82 | 1.67 | 1.98 | 1.14 | 1.04 | 1.25 |
| Gestational age (weeks) | ||||||||||
| 23-24 | 176 | 69.0 | 79 | 31.0 | 12.81 | 9.82 | 16.71 | 16.08 | 12.18 | 21.22 |
| 25-26 | 294 | 70.0 | 126 | 30.0 | 12.23 | 9.92 | 15.07 | 14.27 | 11.42 | 17.82 |
| 27-28 | 468 | 73.6 | 168 | 26.4 | 10.24 | 8.58 | 12.23 | 11.45 | 9.48 | 13.83 |
| 29-30 | 770 | 79.8 | 195 | 20.2 | 7.22 | 6.17 | 8.46 | 8.07 | 6.82 | 9.54 |
| 31-32 | 1532 | 86.9 | 230 | 13.1 | 4.28 | 3.72 | 4.92 | 4.67 | 4.03 | 5.42 |
| 33-34 | 3948 | 88.6 | 506 | 11.4 | 3.66 | 3.33 | 4.02 | 3.76 | 3.41 | 4.16 |
| 35-36 | 14626 | 91.3 | 1393 | 8.7 | 2.72 | 2.57 | 2.88 | 2.68 | 2.52 | 2.84 |
| 37+ | 394483 | 96.6 | 13828 | 3.4 | 1+ | 1+ | ||||
| Sex | ||||||||||
| Male | 215446 | 96.5 | 7781 | 3.5 | 1+ | 1+ | ||||
| Female | 200847 | 95.8 | 8743 | 4.2 | 1.21 | 1.17 | 1.24 | 1.22 | 1.18 | 1.26 |
| Small for gestational age | ||||||||||
| No | 377022 | 96.4 | 14181 | 3.6 | 1+ | 1+ | ||||
| Yes | 39271 | 94.4 | 2343 | 5.6 | 1.59 | 1.52 | 1.66 | 1.34 | 1.27 | 1.40 |
|
| ||||||||||
| Total | 416297 | 96.2 | 16525 | 3.8 | ||||||
In some cases the sum does not add up to the total because of missing values.
NE = Item risk not estimated because of collinearity with “previous deliveries” variable.
°Including all the above listed variables.