Cervical interleukin-6 as a predictive test for preterm delivery in symptomatic women: preliminary results

Abstract

Objective: The aim of this study is to assess the efficacy of cervical interleukin-6 (IL-6) compared with cervical length and its association in the prediction of preterm delivery in symptomatic women.

Study design: Observational prospective study was performed at Hospital Universitario La Fe, Valencia (Spain).

Sample: 100 women between 24 and 34 weeks gestational age, with threatened preterm delivery and intact membranes during the period 2006-2008.

Methods: Transvaginal scan to assess cervical length was performed and cervical swab for IL-6 detection was taken. Statistical analysis included Chi-square test, receiver operating characteristic (ROC) curve analysis, COX regression, logistic regression, and Kaplan-Meier survival analysis.

Results: The prevalence of preterm delivery at <37 weeks was 35% and at <32 weeks was 5%. Cervical length was <15 mm in 12% and <30 mm in 62% of the cases. Cervical length and IL-6 were useful for prediction of delivery at 48 h, 7 days, <32, and <34 weeks. Using ROC curves, the IL-6 value that showed best accuracy for prediction of preterm delivery was >210 pg/ml. No differences were observed between the area under the curve (AUC) of IL-6 and cervical length for the prediction of preterm delivery. The association of IL-6 (>210 pg/ml) and cervical length (<30 mm) increases the prediction of either alone.

Conclusions: Cervical IL-6 can predict preterm delivery similarly to cervical length; when combined, it adds prognostic information to that provided by sonographic measurement of the cervical length.