Table 1 Patient characteristics
|  | All Patients | Delivery < 34 weeks | Delivery 34 + 0 – 36 + 6 weeks | Delivery ≥ 37 weeks | p-value |
|---|---|---|---|---|---|
n = 109 | n = 16 | n = 20 | n = 73 | ||
Maternal age, years ± SD | 30 ± 5 | 31 ± 4 | 30 ± 5 | 31 ± 5 | 0.536 |
BMI before pregnancy (kg/m2), mean ± SD | 25 ± 6.1 | 29 ± 9.9 | 24 ± 5.4 | 24 ± 4.7 | 0.008 |
Gestational diabetes, n (%) | 16 (14.7) | 6 (37.5) | 0 (0) | 10 (13.7) | 0.007 |
History of preterm birth, n (%) | 20 (18.3) | 5 (31.3) | 3 (15) | 12 (16.4) | 0.401 |
Nullipartity, n (%) | 60 (55) | 8 (50) | 12 (60) | 40 (54.8) | 0.844 |
Multiple gestation, n (%) | 14 (12.8) | 8 (50) | 4 (20) | 2 (2.7) | < 0.001 |
Assisted reproductive technique, n (%) | 11 (10.1) | 7 (43.8) | 2 (10) | 2 (2.7) | < 0.001 |
Cervical length, mm ± SD | 21.8 ± 12.6 | 15.3 ± 12.1 | 18.0 ± 9.8 | 24.3 ± 12.8 | 0.010 |
Gestational age at study entry, weeks ± SD | 26 ± 3.0 | 26 ± 3.0 | 26 ± 2.5 | 26 ± 3.1 | 0.813 |
Gestational age at delivery, weeks ± SD | 37 ± 3.8 | 29 ± 3.3 | 35 ± 1,0 | 39 ± 1.2 | < 0.001 |
Interval to delivery, days ± SD | 75 ± 32.8 | 25 ± 23.4 | 65 ± 20.3 | 88 ± 25.0 | < 0.001 |
Tocolysis, n (%) | 55 (50.1) | 14 (87.5) | 16 (80) | 25 (34) | < 0.001 |
Cerclage pessary, n (%) | 10 (9.2) | 2 (12.5) | 4 (20) | 6 (8,2) | 0.274 |
Antenatal steroid prophylaxis, n (%) | 60 (55) | 14 (87.5) | 18 (90) | 28 (38) | < 0.001 |
CRP (mg/L) at study entry, median (IQR) | 4.5 (2–8) | 9 (4–14) | 6 (3–8) | 4 (2–7) | 0.056 |
Leucocytes (× 103/L) at study entry, median (IQR) | 12.0 (9.8–13.9) | 13.8 (12.7–14.8) | 11.6 (9.4–14.3) | 11.4 (9.8–13.2) | 0.01 |