Preterm Birth, Low Gestational Age, Low Birth Weight, Parity, and Other Determinants of Breech Presentation: Results from a Large Retrospective Population-Based Study
Table 2
Distribution and corresponding odds ratios of cases with gestational age ≥37 weeks, 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
41162
97.4
1113
2.6
1+
1+
25–29
86512
97.0
2690
3.0
1.15
1.07
1.23
1.23
1.14
1.32
30–34
134076
96.5
4862
3.5
1.34
1.25
1.43
1.46
1.36
1.57
35–39
104283
96.3
3965
3.7
1.41
1.31
1.50
1.58
1.47
1.71
40+
27365
96.0
1155
4.0
1.56
1.44
1.70
1.62
1.48
1.78
Maternal education
University
112538
96.4
4144
3.6
1+
1+
High school degree
170611
96.5
6183
3.5
0.98
0.95
1.02
1.06
1.02
1.11
Primary/intermediate school or no education
109644
97.0
3446
3.0
0.85
0.82
0.89
1.07
1.01
1.12
Citizenship
Italian
278611
96.4
10453
3.6
1+
1+
Foreign
115872
97.2
3375
2.8
0.78
0.75
0.81
0.95
0.91
0.996
Albanian
10544
97.0
323
3.0
0.82
0.73
0.91
Chinese
6021
97.7
140
2.3
0.62
0.52
0.73
Egyptian
6855
97.6
166
2.4
0.65
0.55
0.75
Moroccan
15508
97.5
393
2.5
0.68
0.61
0.75
Romanian
13365
96.3
509
3.7
1.02
0.93
1.11
Other
63579
97.2
1844
2.8
0.77
0.74
0.81
Previous delivery
0
198363
95.6
9065
4.4
1+
1+
1
140420
97.6
3515
2.4
0.55
0.53
0.57
0.41
0.39
0.43
2+
48980
98.0
1010
2.0
0.45
0.42
0.48
0.35
0.33
0.38
Previous parity in unidentified number
6566
96.5
235
3.5
0.78
0.69
0.89
0.48
0.42
0.56
Previous cesarean
Nulliparous
198363
95.6
9065
4.4
2.30
2.20
2.40
NE
0
127389
98.0
2536
2.0
1+
1+
1
35829
95.9
1530
4.1
2.15
2.01
2.29
1.41
1.31
1.50
2+
7132
97.0
221
3.0
1.56
1.35
1.79
0.96
0.82
1.11
Previous spontaneous or induced abortion
No
279954
96.6
9990
3.4
1+
1+
Yes
114529
96.8
3838
3.2
0.94
0.90
0.98
1.03
0.99
1.07
PMA
Spontaneous conception
387371
96.7
13423
3.3
1+
1+
Assisted conception
7112
94.6
405
5.4
1.64
1.48
1.82
1.03
0.93
1.14
FIVET
2234
95.1
116
4.9
1.50
1.24
1.81
ICSI
2875
94.2
177
5.8
1.78
1.53
2.07
Other
2003
94.7
112
5.3
1.61
1.33
1.95
Sex
Male
203560
97.0
6397
3.0
1+
1+
Female
190920
96.3
7430
3.7
1.24
1.20
1.28
1.23
1.22
1.31
SGA
No
382060
96.6
13290
3.4
1+
1+
Yes
8294
95.1
423
4.9
1.54
1.47
1.62
1.25
1.19
1.32
Total
394483
96.6
13828
3.4
In some cases the sum does not add up to the total because of missing values.1+ Reference categoryNE = Item risk not estimated because of collinearity with “previous deliveries” variable.Multivariate logistic model including all the variables reported in the column.
