Cervicovaginal interleukin-6 as a predictor of preterm birth in African American women

Background: Identification of women who will deliver preterm may reduce infant morbidity and mortality. In heterogeneous populations, fetal fibronectin (fFN) and interleukin-6 are excellent predictors of women who will not deliver within two weeks. African-Americans are at higher risk for preterm birth than Caucasians. This study compares the diagnostic utility of fFN and interleukin-6 in cervicovaginal fluid (CVF) to predict preterm birth within 14. days of sampling in African-American and Caucasian women. Methods: Interleukin-6 was measured in 667 CVF samples from 580 women with and without symptoms of labor. The utility of CVF interleukin-6 and fFN to predict delivery was determined in the total population and in African-Americans and Caucasians separately. Results: fFN positive (≥ 50. μg/l) results were associated with delivery in ≤ 14. days in African-Americans (Odds Ratios (OR) 8.7; Likelihood Ratio (LR) 3.7) (p< 0.0001) and Caucasians (OR 11.9; LR 5.7) (p< 0.01). A positive interleukin-6 (≥ 250. ng/l) was associated with delivery in ≤ 14. days in African-Americans (OR 12.7; LR 5.25) (p< 0.0001), but not in Caucasians (OR 4.1; LR 3.2) (p= 0.13). Conclusions: CVF interleukin-6 and fFN have similar diagnostic utilities in a diverse population. Interleukin-6 more accurately predicts delivery within 14. days in African-Americans, while fFN is more accurate in Caucasians.