| Risk of delivery at <30+0 (%) | Risk of delivery at <34+0 (%) | Risk of delivery at <37+0 (%) | |
| Positive fFN + CL ⩽25 mm | 7.14 | 38.5 | 46.2 |
| Positive fFN + CL >25 mm | 10.0 | 22.2 | 25.0 |
| Negative fFN + CL ⩽25 mm | 0.0 | 5.5 | 11.8 |
| Negative fFN + CL >25 mm | 0.0 | 3.6 | 10.0 |
fFN, fetal fibronectin.