Cervilenz assessment of cervical length compared to fetal fibronectin in the prediction of preterm delivery in women with threatened preterm labor

Objective. To determine whether cervical length (CL) measured by the Cervilenz™ measuring device is an effective screening tool for the prediction of preterm delivery (PTD) compared to fetal fibronectin (fFN). Methods. We evaluated fFN and CL among women who enrolled into a randomized control trial (RCT) comparing management algorithms for threatened preterm labor between 24 and 34 weeks' gestation. In all subjects, fFN was collected, with CL determined in blinded fashion. The sensitivity, specificity, and positive and negative predictive values (NPV) for fFN or Cervilenz in prediction of PTD within 7 days or prior to 37 weeks were determined. Results. Fifty-two subjects were evaluated. CL < 30 mm correlated with PTD < 7 days (r = 0.31, p = 0.04) and fFN positivity (r = 0.43, p = 0.006). CL < 30 mm and fFN had excellent NPV for PTD < 7 days (97.1 vs. 97.3%), and the area under the receiver operator characteristic curves were similar for prediction of PTD < 7 days (76.6 vs. 75.2%, p = 0.71) or < 37 weeks (56.7 vs. 55.2%, p = 0.71). Conclusions. Measurement of CL with Cervilenz appears to be equivalent to fFN in screening symptomatic women for PTD within 7 days or prior to 37 weeks. Given cost and turnaround time with fFN testing, Cervilenz represents a promising new tool for real time, clinically useful results in the management of women with threatened preterm labor.