Table 2

Odds Ratios for dystocia with 95% confidence intervals according to obstetric characteristics


N 2810

Un-adjusted
OR
Adjusted OR*
(95% CI)
All variables
included
All variables included
except birth weight
Trend† OR
(95% CI)

Infertility treatment prior to current pregnancy






     No
2449
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Yes
184
1.13
0.95 (0.69–1.31)
0.92 (0.65–1.29)
1.09 (0.78–1.53)

     Missing
177





Dilatation of cervix at admission





0.83
(0.80–0.86)
     0–3 cm
1086
1.67
1.63 (1.38–1.92)
1.29 (1.06–1.57)
1.21 (1.00–1.47)

     4–10 cm
1575
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Missing
149





Consistency of cervix at admission






     Tense
585
1.25
1.31 (1.04–1.65)
1.0 (0.79–1.26)
0.98 (0.79–1.23)

     Soft
1794
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Missing
431





Thickness of lower segment at admission






     Thick
583
1.30
1.32 (1.09–1.61)
0.88 (0.69–1.12)
0.91 (0.72–1.14)

     Thin
1712
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Missing
515





Descent of fetal head at admission






     Above the inter-spinal-line
2367
2.33
2.29 (1.80–2.92)
1.80(1.32–2.45)
1.92 (1.42–2.58)

     At or under the inter-spinal-line
311
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Missing
132





Fetal head-to-cervix contact






     Good
1921
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Poor
159
1.88
1.83 (1.31–2.56)
1.62 (1.09–2.40)
1.57 (1.08–2.27)

     Cannot be assessed
455





     Missing
275





Birth weight





1.001
(1.00–1.00)
     2000–2499 gr
23
0.14
0.14 (0.32–0.60)
0.27 (0.61–1.21)


     2500–2999 gr
282
0.57
0.51 (0.38–0.69)
0.55 (0.40–0.77)


     3000–3499 gr
1040
0.78
0.74 (0.62–0.89)
0.76 (0.62–0.93)


     3500–3999 gr
1016
1 (ref.)
1 (ref.)
1 (ref.)


     4000–4499 gr
392
1.23
1.29 (1.02–1.65)
1.06 (0.83–1.41)


     ≥ 4500 gr
53
1.36
1.37 (0.78–2.41)
1.32 (0.70–2.46)


Epidural analgesia






     No epidural
2284
1 (ref.)
1 (ref.)
1 (ref.)
1 (ref.)

     Epidural analgesia
316
5.49
5.65 (4.33–7.38)
4.65 (3.53–6.13)
4.77 (3.65–6.22)


* Crude Odds Ratios controlled for age, height, pre-pregnancy BMI and physical activity, including a variable for the participating departments (9 levels).

† Test for trend performed on continuous variables. First line: Regression coefficient for change in OR per unit increased, second line: 95% CI.

Kjærgaard et al. BMC Pregnancy and Childbirth 2008 8:45   doi:10.1186/1471-2393-8-45