Table 4.
Unadjusted and adjusted odds ratios for risk factors in singleton term pregnancies in breech and in cephalic presentations during 2004–2014 in Finland
| ≥ 37 Weeks of gestation | Breech (N = 17 044) | Cephalic (N = 687 255) | P value | Odds ratio (95% Cl) | Adjusted odds ratio (95% CI) |
|---|---|---|---|---|---|
| Maternal age < 25 | 304 (1.8%) | 15,496 (2.3%) | < 0.001 | 0.79 (0.70–0.88) | 0.57 (0.51–0.64) |
| Maternal age ≥ 35 | 3313 (19.4%) | 130,687 (19.0%) | < 0.001 | 1.03 (0.99–1.07) | 1.24 (1.19–1.29) |
| Smoking | 2593 (15.2%) | 102,333 (14.9%) | 0.845 | 1.03 (0.98–1.07) | 1.00 (0.95–1.04) |
| Maternal BMI ≥ 25 | 1753 (10.3%) | 79,114 (11.5%) | < 0.001 | 0.88 (0.84–0.93) | 0.90 (0.85–0.96) |
| Maternal BMI ≥ 30 | 588 (3.4%) | 25,854 (3.8%) | 0.56 | 0.91 (0.84–0.99) | 1.03 (0.93–1.14) |
| Nulliparity | 10,387 (60.9%) | 281,094 (40.9%) | < 0.001 | 2.25 (2.19–2.33) | 2.46 (2.37–2.55) |
| Parity ≥ 3 | 910 (5.3%) | 68,532 (10.0%) | < 0.001 | 0.51 (0.48–0.54) | 0.75 (0.70–0.81) |
| Maternal hypothyroidism | 131 (0.8%) | 3146 (0.5%) | < 0.001 | 1.68 (1.41–2.01) | 1.53 (1.28–1.82) |
| Maternal hyperthyroidism | 22 (0.1%) | 634 (0.1%) | 0.082 | 1.40 (0.91–2.14) | 1.46 (0.95–2.24) |
| Pre-gestational diabetes treated with insulin | 24 (0.1%) | 789 (0.1%) | 0.049 | 1.23 (0.82–1.84) | 1.24 (1.00–1.53) |
| Gestational diabetes | 1447 (8.5%) | 57,613 (8.4%) | 0.418 | 1.01 (0.96–1.07) | 1.02 (0.97–1.08) |
| Pre-eclampsia/hypertension | 600 (3.5%) | 21,627 (3.1%) | 0.07 | 1.12 (1.03–1.22) | 0.93 (0.85–1.01) |
| Previous cesarean section | 1847 (10.8%) | 73,575 (10.7%) | < 0.001 | 1.01 (0.97–1.06) | 1.67 (1.58–1.76) |
| IVF | 483 (2.8%) | 14,393 (2.1%) | 0.68 | 1.36 (1.24–1.49) | 0.98 (0.89–1.08) |
| Maternal care for (suspected) damage to fetus by alcohol/drugs | 6 (0.0%) | 734 (0.1%) | 0.001 | 0.33 (0.15–0.74) | 0.27 (0.12–0.60) |
| Placenta praevia | 55 (0.3%) | 1418 (0.2%) | 0.007 | 1.57 (1.20–2.05) | 1.45 (1.11–1.91) |
| Placental abruption | 23 (0.1%) | 995 (0.1%) | 0.496 | 0.93 (0.62–1.41) | 0.87 (0.75–1.31) |
| PROM | 582 (3.4%) | 12,938 (1.9%) | < 0.001 | 1.84 (1.69–2.01) | 1.58 (1.45–1.72) |
| Oligohydramnios | 453 (2.7%) | 7867 (1.1%) | < 0.001 | 2.36 (2.14–2.60) | 2.02 (1.83–2.22) |
| Congenital anomaly | 2846 (16.7%) | 62 002 (9.0%) | < 0.001 | 2.02 (1.94–2.11) | 1.97 (1.89–2.06) |
| Female sex | 9321 (54.7%) | 336,313 (48.9%) | < 0.001 | 1.26 (1.22–1.30) | 1.28 (1.24–1.32) |
| Birthweight < tenthth percentile | 2153 (12.6%) | 63,826 (9.3%) | < 0.001 | 1.41 (1.35–1.48) | 1.18 (1.12–1.24) |
| Birthweight > 97th percentile | 237 (1.4%) | 15,679 (2.3%) | < 0.001 | 0.60 (0.53–0.69) | 0.75 (0.65–0.85) |
BMI body mass index, IVF in vitro fertilization, PROM premature rupture of membranes