Predicting preterm delivery: comparison of cervicovaginal interleukin (IL)-1beta, IL-6 and IL-8 with fetal fibronectin and cervical dilatation.

Objective: To compare the cervicovaginal cytokines IL-1beta, IL-6 and IL-8 with fetal fibronectin (fFN) and cervical dilatation in the prediction of preterm delivery.
Study Design: Cervicovaginal cytokine concentration and fFN status were measured in 104 women with symptoms of preterm labour and intact membranes between 24(0) and 33(6) weeks and related to delivery within 2 and 7 days.
Results: A group of 18% had cervical dilatation > or = 1cm and 18% were positive for fFN. Preterm delivery within 2 and 7 days occurred in 5 and 12%, respectively. Only IL-6 demonstrated any ability to predict delivery within 2 and 7 days (area under the ROC curve = 0.63 and 0.75, respectively). Using 35pg/ml (75th centile) as a cut-off, IL-6 had a sensitivity and specificity of 60 and 77% for predicting delivery within 2 days, and 62 and 80% for predicting delivery within 7 days. This is similar to the performance of cervical dilatation or fFN status.
Conclusions: Measurement of cervicovaginal cytokines has limited ability to predict imminent delivery apart from cervicovaginal IL-6 concentrations, which, in this population, is equivalent to that of fFN status and cervical dilatation > or = 1cm.