Table 2. Maternal baseline characteristics and sonographic findings.
| Variables | No sPTD (n = 104) | sPTD (n = 26) | P value |
|---|---|---|---|
| Age, yr | 33.90 (31.00–36.00) | 32.20 (30.00–36.00) | 0.597 |
| Multiparity | 68 (65.4) | 14 (53.8) | 0.364 |
| Prior sPTD | 10 (9.6) | 5 (19.2) | 0.179 |
| Prepregnancy BMI, kg/m2 | 20.99 (19.34–22.69) | 19.33 (18.33–21.35) | 0.009 |
| DM | 2 (1.9) | 1 (3.8) | 0.491 |
| HTN | 0 (0.0) | 1 (3.8) | 0.200 |
| Smoking | 1 (1.0) | 0 (0.0) | 1.000 |
| GA at exam, wk | 24.71 (21.86–29.14) | 23.14 (20.86–27.14) | 0.131 |
| CL, cm | 2.10 (1.81–2.30) | 1.83 (1.34–2.30) | 0.148 |
| Funneling | 19 (18.3) | 12 (46.2) | 0.005 |
| IOS strain | 0.30 (0.23–0.37) | 0.29 (0.25–0.36) | 0.965 |
| EOS strain | 0.34 (0.26–0.39) | 0.32 (0.24–0.44) | 1.000 |
| IOS/EOS | 0.88 (0.76–1.03) | 0.89 (0.81–0.99) | 0.864 |
| Strain mean level within 0.5 cm | 0.32 (0.25–0.40) | 0.31 (0.27–0.41) | 0.723 |
| Strain mean level within 1.0 cm | 0.31 (0.25–0.39) | 0.31 (0.24–0.39) | 0.930 |
| Strain mean level within 1.5 cm | 0.33 (0.27–0.40) | 0.32 (0.26–0.41) | 0.894 |
| ECI within 0.5 cm | 5.68 (3.96–7.38) | 6.21 (4.57–8.91) | 0.206 |
| ECI within 1.0 cm | 4.85 (3.35–5.95) | 5.50 (4.07–7.78) | 0.067 |
| ECI within 1.5 cm | 4.30 (3.11–5.14) | 5.09 (3.70–6.95) | 0.056 |
| Hardness ratio within 0.5 cm | 56.37 (41.96–71.22) | 57.19 (37.23–65.72) | 0.773 |
| Hardness ratio within 1.0 cm | 57.63 (44.73–71.58) | 57.42 (40.44–72.87) | 0.961 |
| Hardness ratio within 1.5 cm | 52.88 (41.55–66.00) | 58.13 (38.50–68.58) | 0.868 |
Data are presented as the median (interquartile range) or number (%).
P values less than 0.05 are shown in bold.
sPTD = spontaneous preterm delivery, BMI = body mass index, DM = diabetes mellitus, HTN = hypertension, GA = gestational age, CL = cervical length, IOS = internal os of cervix, EOS = external os of cervix, ECI = elasticity contrast index.