Table 5 Prediction of labour duration ≥ 24 hrs -- Bishop score vs. cervical resistivity with 12 mm probe (data shown for 4 frequencies 9.8-78.1 kHz).
Correlation coefficient | AUC (95% CI) | Optimal cut-off value | Sensitivity % (95% CI) | Specificity % (95% CI) | +LR | -LR | PPV (%) | NPV (%) | |
|---|---|---|---|---|---|---|---|---|---|
Bishop score | -0.05 | 0.54 (0.47 - 0.61) | ≤ 3 | 34.6 (17 - 56) | 86.0 (80 - 91) | 2.46 | 0.76 | 27 | 90 |
Frequency of CR | |||||||||
9.8 kHz | 0.09 | 0.60 (0.53-0.67) | >1.93 Ω.m | 92 (70.8 - 98.6) | 29 (24.6 - 38.9) | 1.33 | 0.29 | 15.3 | 96.2 |
19.5 kHz | 0.14* | 0.65 (0.58-0.72)* | >2.30 Ω.m | 58.3 (37.0 -- 78.0) | 66 (58.0 -- 73.0) | 1.70 | 0.63 | 19.0 | 92.0 |
39.1 kHz | 0.16* | 0.66 (0.59 --0.73)* | >2.25 Ω.m | 75.00 (49.8 - 89.2) | 56.00 (48.3 - 63.5) | 1.70 | 0.45 | 19.0 | 94.2 |
78.1 kHz | 0.16* | 0.65 (0.58-0.72)* | >2.27 Ω.m | 70.8 (45.1 - 86.1) | 58.9(52.3 - 67.3) | 1.72 | 0.50 | 19.1 | 93.6 |