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133: Interleukin-6 levels in cervicovaginal fluid early in pregnancy are elevated in women who deliver preterm

      Objective

      Given the association between intrauterine inflammation and early spontaneous preterm delivery (SPTD), we sought to determine if screening cervicovaginal fluid samples early in pregnancy for inflammatory proteins that are associated with fetal membrane degradation (interleukin-6 [IL-6], neutrophil collagenase [matrix metalloproteinase-8, MMP-8]) could identify women at risk for early SPTD.

      Study Design

      Cervicovaginal fluid samples were collected at initial prenatal visits (<20 weeks′ gestation) in a large cohort of women (N=1,508) presenting for routine prenatal care. Levels of IL-6 and MMP-8 were determined in each sample by ELISA, and IL-6 and MMP-8 levels were normalized to total protein (TP) levels in each sample. The primary outcome of interest was SPTD at <35 weeks of gestation. Because IL-6/TP and MMP-8/TP levels were not normally distributed, comparisons were made between outcomes groups using Wilcoxon rank sum tests.

      Results

      Among women who experienced SPTD at <35 weeks (N=75), rank scores of IL-6/TP were significantly greater than rank scores of women who delivered at term (>37 weeks, P=0.008). However, IL-6/TP levels among all SPTDs (<37 weeks, N=151) were not significantly greater than term deliveries (P=0.29). Rank scores of MMP-8/TP were not significantly different among women who experienced SPTD at <35 weeks compared to women with term deliveries (P=0.88). After controlling for confounders (history of SPTD, maternal race, bacterial vaginosis, sexually transmitted diseases, and periodontal disease) using multivariable logistic regression, the relationship between IL-6/TP and SPTD at <35 weeks remained significant (P=0.024).

      Conclusion

      Spontaneous preterm delivery at less than 37 weeks of gestation is multi-factorial. However, inflammation is closely associated with early SPTD, and this study suggests that inflammatory mediators such as IL-6 in cervicovaginal fluid samples may be useful as non-invasive biomarkers for early SPTD.