[Fetal fibronectin as a predictor of preterm delivery in patients with preterm contractions and cervical changes]

The purpose of the study was to assess the clinical value of fetal fibronectin assay in the group of women presenting with preterm contractions and cervical changes.

We prospectively evaluated 82 patients between 23-34 weeks of gestation presenting with signs and symptoms of preterm labor, intact membranes and cervical dilatation < 3 cm. In all cases cervico-vaginal samples were collected and assayed for the presence of fetal fibronectin. The primary outcome was delivery < or = 28 days from examination.

The rate of preterm delivery (< 37 weeks) was 25.6% (21/82) and 17.1% (14/82) of the patients delivered < or = 28 days from the examination. The mean Bishop score was significantly higher in patients delivered < 28 days (5.9 +/- 1.2 vs 4.7 +/- 1.4; p = 0.004). Positive result of fFN (> 0.05 mg/ml) was found in 71.4% of patients that were delivered < or = 28 days and in 7.4% delivered > 28 days (p < 0.001). For predicting delivery < or = 28 days the positive fFN testing had sensitivity of 71.4%, specificity of 92.7%, PPV of 66.7% and NPV of 94%. The cutoff value for Bishop's score > or = 5 had sensitivity of 85.7% and specificity of 48.5%. Performing fFN testing only in patients with Bishop score > or = 5 resulted in the sensitivity of 71.4%, specificity of 95.6%, PPV of 76.9% and NPV of 94.2%.

Fetal fibronectin is a very good predictor of imminent preterm delivery. It needs further research whether performing of the fFN assay can be limited only to the patients with the estimated Bishop's score > or = 5.