Table 2.
Unadjusted and adjusted odds ratios for risk factors in singleton very preterm 28 + 0 to 31 + 6 weeks of gestational age fetuses in breech and in cephalic presentations during 2004–2014 in Finland
| 28–31 Weeks of gestation | Breech (N = 705) | Cephalic (N = 3877) | P value | Odds ratio (95% Cl) | Adjusted odds ratio (95% CI) |
|---|---|---|---|---|---|
| Maternal age < 25 | 10 (1.4%) | 108 (2.8%) | < 0.001 | 0.50 (0.26–0.96) | 0.57 (0.29–1.10) |
| Maternal age ≥ 35 | 182 (25.8%) | 954 (24.6%) | 0.095 | 1.07 (0.89–1.28) | 0.97 (0.80–1.18) |
| Smoking | 105 (14.9%) | 700 (18.1%) | 0.064 | 0.79 (0.64–0.99) | 0.81 (0.64–1.01) |
| Maternal BMI ≥ 25 | 109 (15.5%) | 532 (13.7%) | 0.124 | 1.15 (0.92–1.44) | 1.24 (0.94–1.63) |
| Maternal BMI ≥ 30 | 33 (4.7%) | 207 (5.3%) | 0.053 | 0.87 (0.60–1.27) | 0.64 (0.41–1.01) |
| Nulliparity | 323 (45.8%) | 1972 (50.9%) | 0.121 | 0.82 (0.70–0.96) | 0.86 (0.71–1.04) |
| Parity ≥ 3 | 96 (13.6%) | 412 (10.6%) | 0.202 | 1.33 (1.04–1.68) | 1.19 (0.91–1.54) |
| Maternal hypothyroidism | 8 (1.1%) | 35 (0.9%) | 0.888 | 1.26 (0.58–2.73) | 1.06 (0.48–2.34) |
| Maternal hyperthyroidism | 3 (0.4%) | 6 (0.2%) | 0.227 | 2.76 (0.69–11.05) | 2.38 (0.58–9.72) |
| Pre-gestational diabetes treated with insulin | 5 (0.7%) | 16 (0.4%) | 0.155 | 1.72 (0.63–4.72) | 1.39 (0.88–2.18) |
| Gestational diabetes | 59 (8.4%) | 248 (6.4%) | 0.086 | 1.34 (0.99–1.80) | 1.31 (0.96–1.79) |
| Pre-eclampsia/hypertension | 114 (16.2%) | 514 (13.3%) | 0.023 | 1.26 (1.01–1.57) | 1.31 (1.04–1.66) |
| Previous cesarean section | 128 (18.2%) | 519 (15.2%) | 0.443 | 1.23 (1.00–1.52) | 1.10 (0.86–1.40) |
| IVF | 22 (3.1%) | 169 (4.4%) | 0.122 | 0.71 (0.45–1.11) | 0.68 (0.41–1.11) |
| Maternal care for (suspected) damage to fetus by alcohol/drugs | 0 (0.0%) | 9 (0.2%) | 0.973 | ||
| Placenta praevia | 9 (1.3%) | 133 (3.4%) | 0.004 | 0.36 (0.18–0.72) | 0.36 (0.18–0.72) |
| Placental abruption | 32 (4.5%) | 232 (6.0%) | 0.225 | 0.75 (0.51–1.09) | 0.79 (0.54–1.16) |
| PPROM | 188 (26.7%) | 764 (19.7%) | < 0.001 | 1.48 (1.23–1.78) | 1.61 (1.32–1.96) |
| Oligohydramnios | 26 (3.7%) | 73 (1.9%) | 0.038 | 2.00 (1.27–3.15) | 1.65 (1.03–2.64) |
| Congenital anomaly | 183 (26.0%) | 946 (24.4%) | 0.453 | 1.09 (0.90–1.31) | 1.08 (0.89–1.30) |
| Female sex | 315 (44.7%) | 1739 (44.9%) | 0.924 | 0.99 (0.84–1.17) | 0.99 (0.84–1.17) |
| Birthweight < 10th percentile | 93 (13.2%) | 348 (9.0%) | 0.002 | 1.54 (1.21–1.97) | 1.57 (1.19–2.08) |
| Birthweight > 97th percentile | 8 (1.1%) | 97 (2.5%) | 0.022 | 0.45 (0.22–0.92) | 0.42 (0.20–0.89) |
BMI body mass index, IVF in vitro fertilization, PPROM preterm premature rupture of membranes